Aspiration thrombectomy system and methods for thrombus removal with aspiration catheter

ABSTRACT

A clot removal system comprises a catheter, a vacuum source, and a controller. The catheter comprises a proximal end, a distal end, and controller operating parameters and defines a lumen configured to be filled with a liquid column having a proximal portion. The vacuum source is configured to supply vacuum. The controller is configured to carry out a control pattern of turning on and off the vacuum based upon the controller operating parameters and is configured to receive the controller operating parameters in an automatic response to the catheter being operatively connected to at least one of the vacuum source and the controller and, responsive to the connection, to carry out the control pattern to change a level of vacuum at the distal end of the catheter.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. patent application Ser. No.16/899,514, filed on Jun. 11, 2020, which is a continuation applicationof:

-   -   U.S. patent application Ser. No. 16/681,564, filed on Nov. 12,        2019, now U.S. Pat. No. 10,722,253, issued Jul. 28, 2020, which        is a continuation of U.S. patent application Ser. No.        16/516,232, filed on Jul. 18, 2019, now U.S. Pat. No.        10,531,883, issued Jan. 14, 2020, which claims the benefit of        U.S. Provisional Application Ser. No. 62/701,086, filed Jul. 20,        2018, and 62/750,011, filed Oct. 24, 2018; and    -   under 35 U.S.C. § 120, International Application No.        PCT/US2019/042546, filed Jul. 19, 2019, which designated the        United States, which international application claims the        priority, under 35 U.S.C. § 119, of U.S. patent application Ser.        No. 16/516,232, filed on Jul. 18, 2019, which claims the benefit        of U.S. Provisional Application Ser. No. 62/701,086, filed Jul.        20, 2018, and 62/750,011, filed Oct. 24, 2018.        The entire disclosures of which are hereby incorporated herein        by reference in their entireties.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

Not Applicable

TECHNICAL FIELD

The present systems, apparatuses, and methods lie in the field ofthrombus removal. The present disclosure relates to an aspirationthrombectomy system and methods for thrombus removal with aspirationcatheter.

BACKGROUND

Ischemic strokes are usually caused by a blood clot that blocks or plugsa blood vessel in the brain. This blockage prevents blood from flowingto the brain. Within minutes, brain cells begin to die, which, if nottreated rapidly, causes brain damage or death. The costs associated withremoving a clot are significant. Most treatments involve thrombectomy:the removal of the clot by aspiration, mechanical retrieval, or somecombination thereof.

Removal by aspiration is effected by placing a source of vacuum, e.g.,an aspiration or vacuum catheter, upstream of the clot and drawing theclot into or against the distal end of the catheter. Conceptually,aspiration is effective but some significant problems occur in practice.The basic configuration for an aspiration catheter includes a length ofhollow catheter having a proximal end fluidically connected to a vacuumor suction pump. In this configuration, operation of the suction pumpcauses fluid and particulates at the distal end of the catheter to enterthe distal opening of the hollow lumen and travel to the proximal end ofthe lumen near or into the suction pump. Conventional aspirationcatheters are threaded through a balloon guide catheter. In oneexemplary procedure, the balloon of the guide catheter is guided intothe internal carotid artery of the brain. The balloon is inflated toocclude the vessel. The aspiration catheter is threaded through theballoon guide catheter and out the distal end of the guide catheter pastthe balloon. The distal end of the aspiration catheter is advanced tothe clot that is occluding the brain vessel. Suction connected to theaspiration catheter is turned on to cause flow reversal. Ideally, thissystem aspirates the clot entirely out of the neurovasculature and tothe proximal end of the aspiration catheter so that extraction andre-establishment of blood flow could be confirmed. In practice, however,this rarely occurs.

Thrombi are frequently of a larger diameter than the catheter being usedto aspirate them. For aspiration to be successful, the thrombus mustdeform to conform to the inner diameter of the aspiration catheter.During conventional aspirations, it is common for applied vacuum topartially draw a thrombus into the distal opening of the aspirationcatheter's lumen, thereby deforming some of the thrombus to thecatheter's inner diameter. At this point, the thrombus becomes lodgedcompletely within, partially within, or at the distal opening of theaspiration catheter, a condition that can be referred to as corked orcorking. In effect, the distal end becomes a suction cup grasper for theclot. When this situation occurs, a surgeon's only option is to use theaspiration catheter as a fishing line to pull the clot back through theballoon guide and out of body. The other option is not viable, that is,reversing the suction to pressurize the clot and eject it forcibly anduncontrollably out of the distal opening of the aspiration catheter.Such action is dangerous to the patient for many reasons, the primaryone being that forcibly and uncontrollably ejecting the clot may causethe clot to move further distally within the vessel in which it wasoriginally lodged. That distal movement would not only cause the clot tobe further within the vessel—i.e., in an even smaller diameter of thevessel than when it was originally lodged—but it could permanently lodgethe clot into that vessel, making it impossible to remove, or it couldburst the vessel. Those of skill in the art know that these situationsare to be avoided because of the serious potential risks to the patient.

Even when the surgeon uses the aspiration catheter to fish out the clot,there is no assurance that the entirety of the clot will be removed.Pieces of the clot can break off during movement, when that occurs, thepieces re-embolize within the same vessel or within different vesselsthat might be even more difficult to remove.

When all or most of the clot is drawn out from the patient, it isdifficult to confirm that the entire thrombus was removed. A significantdisadvantage of current thrombus removal devices is the inability of asurgeon to ascertain thrombus capture/removal without the fullwithdrawal of a given therapeutic device from a patient's anatomy. Evensystems capable of fully aspirating a given thrombus are problematic,because the reservoirs into which aspirated contents are deposited arelocated outside of the sterile field in an operating room setting. Thislocation, outside the sterile field, makes it difficult or impossiblefor physicians operating aspiration catheters to easily visualize andappraise aspirated thrombus material.

To confirm thrombus removal can require the surgeon to attemptaspiration again. The aspiration and balloon guide catheters have to becleaned out, access to distal anatomy has to be re-established, and,when the aspiration catheter finally is located back at the embolismsite, the same issues may be present again with whatever embolusmaterial remains. A disadvantage of these procedures is the significantincrease in procedure time, which not only significantly increases thecost (as each minute in an operating room is expensive), it alsoincreases the surgeon's stress, which decreases the success rate of theoperation.

First-pass recanalization rate is a metric used to determine theefficacy of thrombectomy systems. Most current systems offer rates ofbetween 30% and 60%. A system that increases the first-passrecanalization rate is valuable and desirable.

Even with an attempt to maintain vacuum pressure utilizing manualperiodic cycling, prior art systems are not capable of avoiding positivepressures at the distal end of the catheter. Prior art systems are notable to react quickly enough to keep the distal end of the catheter fromexperiencing a positive pressure. When positive pressure exists at thedistal end of the lumen, liquid from inside the lumen exits out from thedistal end of the catheter in a distal direction. This is referred to asforward flow. The prior art do not have a fast enough reaction time toquell forward flow. Forward flow, therefore, can and does remove thrombioff of the distal end and risk sending thrombi further distally in thevasculature. Such systems cannot guarantee removing all forward floweliminating positive pressure at the distal end of the catheter.

Thus, a need exists to overcome the problems with the prior art systems,designs, and processes as discussed above.

SUMMARY

The systems, apparatuses, and methods described provide an aspirationthrombectomy system and methods for thrombus removal with an aspirationthrombectomy system that overcome the hereinafore-mentioneddisadvantages of the heretofore-known devices and methods of thisgeneral type and that provide such features with increased first-passrecanalization rate by completely pulling the embolus out and, thereby,reducing the instance of aspiration catheter obstruction/clogging by theembolus.

The systems, apparatuses, and methods provide an aspiration thrombectomysystem that completely vacuums up the clot so that clots are no longerdragged out of vasculature while half hanging out of a catheter tip. Theaspiration thrombectomy system moves the vacuumed clot all the way tothe proximal end of the vacuum channel and allows the surgeon to confirmrecanalization of the vessel in which the clot formerly resided (forexample, by injecting contrast through the catheter that remains inplace after clot removal) and provides structure to indicate to thesurgeon that the thrombus has been removed and that flow has beenrestored.

The systems, apparatuses, and methods provide an aspiration thrombectomysystem that can be coupled with conventional aspiration catheters tosignificantly increase the efficacy of such catheter and pump systems.Vacuum level is indicated herein in two different ways:

-   -   1) as the absolute level of pressure, where a “high vacuum”        approaches zero absolute pressure. This is the “absolute        pressure” way of measuring vacuum. A perfect vacuum would be        zero, and atmospheric pressure would be indicated by measuring        the height of a column of mercury that can be supported by a        standard atmosphere (760 mm Hg). Hence, lower values indicate an        increased level of vacuum relative to the ambient atmospheric        pressure.    -   2) The pressure relative to atmospheric pressure may be        indicated. This way of measuring pressure relative to a standard        atmospheric pressure is known as “gage pressure.” The most        common way of measuring pressure in the vacuum realm (below        atmospheric pressure) is by using a gage calibrated so that one        atmosphere reads zero (standard atmospheric pressure), and the        highest possible level of vacuum would be indicated as “29.92        inches of mercury” Common mechanical vacuum gauges work this        way, so this usage has become common.        Herein, the “gage pressure” is used as method of indicating        vacuum level; i.e., “zero inches of mercury” means atmospheric        pressure, no suction at all. A high number (e.g., 25″ Hg) means        a high level of vacuum suction. (The highest possible level of        vacuum measured this way would be 29.92″ Hg.) “Vacuum” as used        herein is a condition below normal atmospheric pressure. In the        instant application, the units of pressure for vacuum is pounds        per square inch (“PSI”).psi”), inches of mercury, or mmHg.        Depending on the context of use of the word vacuum, a “high”        vacuum is referred to herein as a low pressure that is lower        than atmospheric pressure. Vacuum also refers to a negative        pressure(s) and a pressure above atmospheric pressure is        referred to as a positive pressure. In some instances, however,        use of the word “high” with respect to pressure can mean a        greater negative or can mean a greater positive based on the        context. Likewise, use of the words “low” or “lower” with        respect to pressure can mean a lesser negative or can mean a        lesser positive based on the context

Thrombi are frequently of a larger diameter than the catheter being usedto aspirate them. In order for aspiration to be successful, the thrombusmust deform to conform to the inner diameter of the aspiration catheter.During conventional aspirations, it is common for applied vacuum topartially draw a thrombus into the distal opening of the aspirationcatheter's lumen. At this point, the thrombus becomes stuck with some ofthe thrombus resting within the catheter's inner diameter and some ofthe thrombus protruding from the distal end.

The systems, apparatuses, and methods provide an aspiration thrombectomysystem with an unclogging structure and technique that temporarily haltsvacuum at the distal end of the aspiration catheter, pushes the thrombusdistally out of the lumen, and then re-applies vacuum—anocclusion-vacuum-pressure sequence of operation. Upon re-application ofthe vacuum, the thrombus accelerates back into the catheter and deformsto a diameter allowing it to be completely aspirated. Each halting ofthe vacuum, thrombus pushing, and reapplication of the vacuum iscontrolled by the surgeon.

The systems and methods operate an aspiration/suction catheter with amechanism to stop the vacuum and then press the distal fluid column inreverse, i.e., a positive displacement without a check valve, referredto herein as a column shift. All functions can be controlled with asingle handle, including vacuum shut off and column shift while limitingthe amount and the force for the column shift. When the controller isactuated, a positive amount of exit flow is created without possibilityof overshooting. The exiting movement of fluid is limited to a specificvolume and/or pressure and is automatically and precisely controlled. Itis the user who controls when the column shift occurs and when itreturns. A trap is disposed at an exit to catch and display thethrombus. A vent can be opened to atmosphere to clear fluid in the trapand show what thrombus remains.

With the foregoing and other objects in view, there is provided, avacuum catheter for removing an object from within a human vesselcomprising a vacuum tube defining an interior vacuum channel comprisinga proximal opening for receiving application of vacuum and a distalcapture opening fluidically connected to the proximal opening, thedistal capture opening configured to receive therein the objectresponsive to application of the vacuum, and comprising an intermediatesection between the proximal opening and the distal capture opening, anda vacuum interruption controller comprising a body through which aportion of the intermediate section passes and an extrusion compressormovably disposed with respect to the body towards and away from theportion of the intermediate section such that, in a rest state, theextrusion compressor does not occlude the vacuum channel and, in anactuated state, the extrusion compressor first occludes the vacuumchannel and then moves fluid disposed between the portion of theintermediate section and the distal capture opening a given distancedistally towards the distal capture opening.

In accordance with another feature, there is provided a vacuum pumpselectively applying vacuum to the proximal opening.

In accordance with a further feature, the vacuum tube has a proximalportion and which further comprises a catheter body surrounding thevacuum tube and configured to steer at least the proximal portion of thevacuum tube.

In accordance with an added feature, the vacuum tube has a proximalportion sized to fit within the Circle of Willis in a brain and theobject is a blood clot adjacent the Circle of Willis.

With the foregoing and other objects in view, there is provided, a clotremoval system comprising a catheter having a distal end and defining alumen filled with a liquid column having a proximal portion and a distalportion, a controllable vacuum valve, a vacuum source fluidicallyconnected to the vacuum valve, a controllable vent valve having a ventliquid input, a vent fluid source containing a vent liquid andfluidically connected to the vent valve to retain the vent liquid at thevent fluid input, a manifold connected to the catheter, to the vacuumvalve, and to the vent valve, the manifold fluidically connecting theproximal portion of the liquid column in the lumen to the vacuum sourcethrough the vacuum valve and to the vent fluid source through the ventvalve, a controller connected to the vacuum valve and the vent valve andconfigured to selectively open and close the vacuum valve and the ventvalve such that, responsive to opening the vacuum valve, the vacuumsource is fluidically connected to the liquid column in the lumen and,responsive to opening the vent valve, the vent fluid source isfluidically connected to the liquid column in the lumen, the controllerconfigured to cyclically open and close the vacuum valve and the ventvalve to change a level of vacuum at the distal end and prevent forwardflow of the distal portion out from the distal end during each cycle.

With the objects in view, there is also provided a clot removal systemcomprising a catheter having a distal end and defining a lumen filledwith a liquid column having a proximal portion and a distal portion, acontrollable vacuum valve, a vacuum source fluidically connected to thevacuum valve, a controllable vent valve having a vent liquid input, avent fluid source containing a vent liquid and fluidically connected tothe vent valve to retain the vent liquid at the vent fluid input, amanifold connected to the catheter, to the vacuum valve, and to the ventvalve, the manifold fluidically connecting the proximal portion of theliquid column in the lumen to the vacuum source through the vacuum valveand to the vent fluid source through the vent valve, a controllerconnected to the vacuum valve and the vent valve and configured toselectively open and close the vacuum valve and the vent valve such thatresponsive to opening the vacuum valve, the vacuum source is fluidicallyconnected to the liquid column in the lumen and responsive to openingthe vent valve, the vent fluid source is fluidically connected to theliquid column in the lumen, the controller configured to cyclically openand close the vacuum valve and the vent valve in a repeated cyclecomprising a double-closed state in which the vacuum valve is closed andthe vent valve is closed to change a level of vacuum at the distal endand prevent forward flow of the distal portion out from the distal endduring each cycle, and a time of the double-closed state is no greaterthan approximately 30 ms.

With the objects in view, there is also provided a clot removal systemcomprising a catheter having a distal end and defining a lumen filledwith a liquid column having a proximal portion and a distal portion, avacuum source, a vent liquid source, and a vacuum and vent controlsystem configured to cyclically connect or disconnect the vacuum sourceand the vent liquid source to change a level of vacuum at the distal endand substantially prevent forward flow.

With the objects in view, there is also provided a clot removal systemcomprising a catheter having a distal end and defining a lumen filledwith a liquid column having a proximal portion and a distal portion, avacuum source, a vent liquid source, and a vacuum and vent controlsystem configured to cyclically fluidically connect to the proximalportion at least one of vacuum from the vacuum source, vent liquid fromthe vent liquid source, and neither the vacuum nor the vent liquid, andthereby change a level of vacuum at the distal end and substantiallyprevent forward flow.

In accordance with another feature, the controller is configured tocyclically open and close the vacuum valve and the vent valve in arepeated cycle comprising a double-closed state in which the vacuumvalve is closed and the vent valve is closed.

In accordance with a further feature, a time of the double-closed stateis no greater than 30 ms.

In accordance with an added feature, the controller is configured tocyclically open and close the vacuum valve and the vent valve in arepeated cycle comprising a vent-only state in which the vacuum valve isclosed and the vent valve is open.

In accordance with an additional feature, a time of the vent-only stateis no greater than 50 ms.

In accordance with yet another feature, the controller is configured toselectively open and close the vacuum valve and the vent valve cycle ina repeated cycle comprising a vacuum-only state in which the vacuumvalve is open and the vent valve is closed, a first double-closed statein which the vacuum valve is closed and the vent valve is closed, avent-only state in which the vacuum valve is closed and the vent valveis open, and a second double-closed state in which the vacuum valve isclosed and the vent valve is closed.

In accordance with yet a further feature, a time between an opening ofthe vent valve and a closing of the vent valve is between approximately10 ms and approximately 50 ms.

In accordance with yet an added feature, a period of the cycle isbetween approximately 6 Hz and approximately 16 Hz.

In accordance with yet an additional feature, a period of the cycle isbetween approximately 8 Hz and 12 Hz.

In accordance with again another feature, the change in the level ofvacuum at the distal end is greater than approximately 15 inHg in nogreater than approximately 50 ms.

In accordance with again another feature, the change in the level ofvacuum at the distal end is greater than approximately 20 inHg and nogreater than approximately 30 ms; and

In accordance with again another feature, the change in the level ofvacuum at the distal end is greater than approximately 25 inHg and nogreater than approximately 20 ms.

In accordance with again an added feature, the lumen has an internaldiameter of between approximately 0.038″ and approximately 0.106″ andthe controller is configured to cyclically open and close the vacuumvalve and the vent valve at a frequency of between 2 and 16 Hz.

In accordance with again an additional feature, the lumen has aninternal diameter of between approximately 0.068″ and approximately0.088″ and the controller is configured to cyclically open and close thevacuum valve and the vent valve at a frequency of between 2 and 16 Hz.

In accordance with still another feature, the controller is configuredto cyclically open and close the vacuum valve and the vent valve in arepeated cycle and prevent forward flow of the distal portion out fromthe distal end during each cycle by regulating timing of the vent valve.In accordance with still a further feature, the controller is configuredto cyclically open and close the vacuum valve and the vent valve toretain a level of pressure at the distal end at less than physiologicalpressure.

In accordance with a concomitant feature, there is provided a shaft andthe vacuum valve and the vent valve are mounted together on the shaft.

Operation of a ROAR process as described hereinbelow successfullyremoves thrombi for two reasons. First, the ROAR effect overcomes thestatic friction of a clot that is fixed or “stuck” on the catheter tipwhile under constant suction. The ROAR process provides anoscillating/alternating displacement that causes the clot to “shuttle”back and forth to overcome static frictional force. Second, there is amorcellation of the clot that overcomes different clot morphologies aswell as overriding volume and diameter constraints of the small, fixedluminal volume dictated by the micro-anatomic environment.

The systems and methods described and shown herein react quickly enoughto keep pressure at the distal end from going positive. By cycling thevacuum and vent valves at a sufficiently fast rate, a pressuremeasurement at a rate of one thousand samples per section at the distalend of the catheter lumen proves that the distal end of the ROARcatheter does not experience positive pressure and substantially quellsforward flow. The timing between operating the vacuum and vent valvescan be adjusted so that physical mechanisms that would cause distal endpositive pressure can be avoided in both the open flow condition and inthe corked condition.

In accordance with an exemplary embodiment, the distal portion of theliquid column exiting the distal end is limited to no more thanapproximately 2 microliters.

In accordance with an exemplary embodiment, a clot removal systemcomprises a catheter having a distal end and defining a lumen filledwith a liquid column having a proximal portion and a distal portion, avacuum source, a vent fluid source containing a vent liquid, and avacuum and vent control system configured to cyclically fluidicallyconnect to and disconnect from the proximal portion at least one ofvacuum from the vacuum source and vent fluid from the vent fluid source,and thereby change a level of vacuum at the distal end and substantiallyprevent the distal portion of the liquid column from exiting the distalend.

In accordance with an exemplary embodiment, a clot removal systemcomprises a catheter having a distal end and defining a lumen filledwith a liquid column having a proximal portion and a vacuum and ventcontrol system configured to cyclically connect to and disconnect fromthe proximal portion vacuum and vent fluid to create therein a forwardflow pressure pulse and thereby reverse flow in the liquid column andsubstantially prevent the forward flow pressure pulse from reaching thedistal end.

In accordance with an exemplary embodiment, a clot removal systemcomprises a catheter having a distal end and defining a lumen filledwith a liquid column having a proximal portion and a vacuum and ventcontrol system configured to cyclically connect to and disconnect fromthe proximal portion vacuum and vent fluid to create therein a forwardflow pressure pulse and, before the forward flow pressure pulse reachesthe distal end, reverse flow in the liquid column and therebysubstantially prevent the forward flow pressure pulse from reaching thedistal end.

In accordance with an exemplary embodiment, a clot removal systemcomprises a catheter having a distal end and defining a lumen filledwith a liquid column having a proximal portion and a vacuum and ventcontrol system configured to cyclically connect to and disconnect fromthe proximal portion vacuum and vent fluid and thereby allow the liquidcolumn to move and stop to create therein a forward flow pressure pulseand, before the forward flow pressure pulse reaches the distal end,alternate control to reverse flow in the liquid column and therebycontrol the forward flow pressure pulse by substantially preventing theforward flow pressure pulse from reaching the distal end.

In accordance with an exemplary embodiment, the controller is configuredto change the level of vacuum at the distal end in a cycle whilesimultaneously preventing distal movement of the distal portion of theliquid column.

In accordance with an exemplary embodiment, the controller is configuredto selectively open and close the vacuum valve and the vent valve cyclein a repeated cycle comprising a first state in which the vacuum valveis open and the vent valve is closed, a second state in which the vacuumvalve is closed and the vent valve is closed, a third state in which thevacuum valve is closed and the vent valve is open, and a fourth state inwhich the vacuum valve is closed and the vent valve is closed.

In accordance with an exemplary embodiment, a clot removal systemcomprises a catheter defining a lumen filled with a liquid column from aproximal portion to a distal end and a water hammer controllerconfigured to alternatively connect vacuum and/or fluid at atmosphericor body or lower pressure to the lumen, thereby allowing the liquidcolumn to move and stop to create therein a water hammer and, before thewater hammer reaches the distal end, alternate control to reverse flowand thereby control the water hammer by substantially preventing thewater hammer from reaching the distal end.

In accordance with an exemplary embodiment, a clot removal systemcomprises a catheter with a lumen, a vacuum source, a controllablevacuum valve, a vent fluid source, a controllable vent valve, a manifoldconnected to the catheter, to the vacuum valve, and to the vent valve,and a controller controlling the vacuum valve and the vent valve.

In accordance with an exemplary embodiment, the controller is configuredto modulate the vacuum valve and the vent valve in a cycle that,responsive to vacuum being applied to the catheter, the compliance ofthe catheter causes a reduction in volume such that, when the vacuum isclosed and the vent is open, the compliance acts as a spring and thelumen ingests vent fluid in a distal direction and, before a momentuminduced by the ingested fluid reaches the distal end of the catheter,the controller modulates the valves to reverse a direction and quellmovement of the fluid of the fluid and prevent the fluid from exitingthe distal end of the catheter.

In accordance with an exemplary embodiment, a clot removal systemcomprises a catheter having a lumen, a substantially incompressibleconnection tube having interior lumen with a proximal end and a distalend fluidically connected to the lumen, a vacuum source, and avacuum/vent manifold comprising a manifold chamber having an outputfluidically connected to the proximal end, a vacuum line fluidicallyconnected to the manifold and to the vacuum source to present vacuumfrom the source to the manifold chamber, and a vent line fluidicallyconnected to the manifold and to a fluid bath at atmospheric pressure.

In accordance with an exemplary embodiment, the clot removal systemcomprises a fixed cycle with plurality of pinch valves and plurality ofcams mechanically coupled to the valves so that orientations of the camscannot be changed.

In accordance with an exemplary embodiment, the time within which theforward flow pulse is quelled is no greater than approximately 20 ms.

In accordance with an exemplary embodiment, a clot removal systemcomprises a pulsatile vacuum controller configured to alternativelyconnect vacuum and/or fluid at atmospheric/body/slightly lower thanbody/slightly higher than body pressure to the lumen and thereby allowthe liquid column to move and stop to create therein a forward flowpressure pulse and (before the forward flow pressure pulse reaches thedistal end, alternating control to reverse flow and thereby) control theforward flow pressure pulse by substantially preventing the forward flowpressure pulse from reaching the distal end.

With the foregoing and other objects in view, there is provided, a clotremoval system comprising a catheter having a proximal end and a distalend and defining a lumen configured to be filled with a liquid columnhaving a proximal portion, a vacuum pump configured to supply vacuum, avent container holding a vent liquid, a vent valve configured tofluidically communicate with the vent liquid in the vent container andwith the proximal portion of the liquid column at the proximal end ofthe catheter, a vacuum valve configured to fluidically communicate withthe vacuum from the vacuum pump and with the proximal portion of theliquid column at the proximal end of the catheter, and a controllerconfigured to carry out a pre-determined pattern of opening and closingthe vent and vacuum valves to change a level of vacuum at the distal endand, while changing the level of vacuum at the distal end, tosubstantially prevent forward flow of the liquid at a distal end of theliquid column.

With the objects in view, there is also provided a clot removal systemcomprising a catheter having a proximal end and a distal end anddefining a lumen configured to be filled with a liquid column having aproximal portion, a vacuum pump configured to supply vacuum, a ventliquid container holding a vent liquid, a vent valve configured tofluidically communicate with the vent liquid in the liquid container andwith the proximal portion of the liquid column at the proximal end ofthe catheter, a vacuum valve configured to fluidically communicate withthe vacuum from the vacuum pump, and with the proximal portion of theliquid column at the proximal end of the catheter, and a controllerconfigured to carry out a pre-determined cycle of opening and closingthe vent and vacuum valves to change a level of vacuum at the distal endand, during each cycle, to substantially prevent forward flow of liquidat the distal end of the liquid column.

In accordance with another feature, the liquid at the distal end of theliquid column is one or more of albumin, d5 W water, normal saline,half-normal saline, lactated Ringer's solution, and blood, and mixturesthereof.

In accordance with a further feature, there is provided a manifoldcomprising the vent valve, the vacuum valve, and an output and anextension line fluidically connecting the proximal end of the catheterto the output of the manifold.

In accordance with an added feature, a portion of the pre-determinedpattern includes a time period where both the vent and vacuum valves areclosed.

In accordance with an additional feature, the controller is configuredto open and close the vent and vacuum valves in a repeated cyclecomprising a double-closed state in which both the vent and vacuumvalves are closed.

In accordance with yet another feature, a time of the double-closedstate is no greater than 30 ms.

In accordance with yet a further feature, the controller is configuredto open and close the vent and vacuum valves in a repeated cyclecomprising a vent-only state in which the vacuum valve is closed and thevent valve is open, and a time of the vent-only state is no greater than50 ms.

In accordance with yet an added feature, the controller is configured torepeatedly and periodically carry out the pre-determined pattern.

In accordance with yet an additional feature, the controller isconfigured to selectively open and close the vent and vacuum valves in arepeated cycle comprising a vacuum-only state in which the vacuum valveis open and the vent valve is closed, a first double-closed state inwhich the vacuum valve is closed and the vent valve is closed, avent-only state in which the vacuum valve is closed and the vent valveis open, and a second double-closed state in which the vacuum valve isclosed and the vent valve is closed.

In accordance with again another feature, the controller is configuredto selectively open and close the vent and vacuum valves in a repeatedcycle comprising a vacuum-only state in which the vacuum valve is openand the vent valve is closed, followed by a first double-closed state inwhich the vacuum valve is closed and the vent valve is closed and a timeof the first double-closed state is no greater than 30 ms, followed by avent-only state in which the vacuum valve is closed and the vent valveis open, followed by a second double-closed state in which the vacuumvalve is closed and the vent valve is closed.

In accordance with again a further feature, a time between an opening ofthe vent valve and a closing of the vent valve is between approximately10 ms and approximately 50 ms.

In accordance with again an added feature, a frequency of the cycle isbetween approximately 6 Hz and approximately 16 Hz.

In accordance with still another feature, a frequency of the cycle isbetween approximately 8 Hz and 12 Hz.

In accordance with still a further feature, the change in the level ofvacuum at the distal end is one of greater than approximately 15 inHgand occurs in no greater than approximately 50 ms, greater thanapproximately 20 inHg and occurs in no greater than approximately 30 ms,and greater than approximately 25 inHg and occurs in no greater thanapproximately 20 ms.

In accordance with still an added feature, the lumen has a diameter ofbetween approximately 0.038″ and approximately 0.106″ and the controlleris configured to repeatedly and periodically carry out thepre-determined pattern of opening and closing the vent and vacuum valvesat a frequency of between 2 and 16 Hz.

In accordance with still an additional feature, the lumen has aninternal diameter of between approximately 0.068″ and approximately0.088″ and the controller is configured to repeatedly and periodicallycarry out the pre-determined pattern of opening and closing the vent andvacuum valves at a frequency of between 6 and 12 Hz.

In accordance with another feature, the controller is configured to openand close the vent and vacuum valves in a repeated cycle of thepre-determined pattern and prevent forward flow of the distal portionout from the distal end during each cycle by regulating timing of thevent valve.

In accordance with a further feature, the controller is configured toopen and close the vacuum valve and the vent valve in a repeated cycleof the pre-determined pattern to retain a level of pressure at thedistal end at less than physiological pressure.

In accordance with an added feature, the controller is one of amechanical valve controller and an electronic valve controller.

In accordance with a concomitant feature, there is provided a shaft andthe vent and vacuum valves are cam-driven valves with respective camsmounted together on the shaft.

With the foregoing and other objects in view, there is provided, a clotremoval system comprising a catheter comprising a proximal end, a distalend, and controller operating parameters and defining a lumen configuredto be filled with a liquid column having a proximal portion, a vacuumsource configured to supply vacuum, and a controller configured to carryout a control pattern of turning on and off the vacuum based upon thecontroller operating parameters and configured to receive the controlleroperating parameters in an automatic response to the catheter beingoperatively connected to at least one of the vacuum source and thecontroller and, responsive to the connection, to carry out the controlpattern to change a level of vacuum at the distal end of the catheter.

With the objects in view, there is also provided a clot removal systemcomprising a catheter comprising a proximal end, a distal end, andcontroller operating parameters and defining a lumen configured to befilled with a liquid column having a proximal portion, a vacuum sourceconfigured to supply vacuum, a vacuum modulator configured tofluidically communicate with the vacuum from the vacuum source and withthe proximal portion of the liquid column at the proximal end of thecatheter, and a controller configured to carry out a control pattern ofmodulating the vacuum modulator based upon the controller operatingparameters and configured to receive the controller operating parametersin an automatic response to the catheter being operatively connected toat least one of the vacuum modulator and the controller and, responsiveto the connection, to carry out the control pattern to change a level ofvacuum at the distal end of the catheter.

With the objects in view, there is also provided a clot removal systemcomprising a catheter comprising a proximal end, a distal end, andcontroller operating parameters and defining a lumen configured to befilled with a liquid column having a proximal portion, a vacuum sourceconfigured to supply vacuum, a vent container holding a vent liquid, avent valve configured to fluidically communicate with the vent liquid inthe liquid container and with the proximal portion of the liquid columnat the proximal end of the catheter, a vacuum valve configured tofluidically communicate with the vacuum source and the proximal portionof the liquid column at the proximal end of the catheter, and acontroller configured to carry out a control pattern of opening andclosing the vent and vacuum valves based upon the controller operatingparameters and configured to receive the controller operating parametersin an automatic response to the catheter being operatively connected toat least one of the vent valve, the vacuum valve, the vacuum source, andthe controller and, responsive to the connection, to carry out thecontrol pattern to change a level of vacuum at the distal end of thecatheter.

With the objects in view, there is also provided a clot removal systemcomprising a catheter comprising a proximal end, a distal end, andcontroller operating parameters and defining a lumen configured to befilled with a liquid column having a proximal portion and a distal end,a vacuum source configured to supply vacuum, a vent container holding avent liquid, a vent valve configured to fluidically communicate with thevent liquid in the liquid container and with the proximal portion of theliquid column at the proximal end of the catheter, a vacuum valveconfigured to fluidically communicate with the vacuum source and theproximal portion of the liquid column at the proximal end of thecatheter, and a controller configured to carry out a control pattern tochange a level of vacuum at the distal end of the catheter and, whilechanging the level of vacuum at the distal end of the catheter, tosubstantially prevent forward flow of the liquid at the distal end ofthe liquid column and configured to operate the vent and vacuum valvesbased upon the controller operating parameters in an automatic responseto the catheter being operatively connected to at least one of the ventvalve, the vacuum valve, the controller, and the vacuum source.

In accordance with another feature, the controller operating parametersare stored in the catheter and are provided to the controller responsiveto the connection.

In accordance with a further feature, the catheter comprises anextension line having a first end connected to the catheter and a secondend connected to at least one of the vacuum source and the controllerand comprising the controller operating parameters and, responsive tothe connection configured to provide the controller operating parametersto the controller and fluidically connecting the proximal end of thecatheter with the vacuum source.

In accordance with an added feature, the controller is part of thevacuum source and the controller is configured to receive the controlleroperating parameters in the automatic response to the catheter beingoperatively connected to the vacuum source.

In accordance with an additional feature, the controller is separatefrom the vacuum source and the controller is configured to receive thecontroller operating parameters in the automatic response to thecatheter being operatively connected to the controller.

In accordance with yet another feature, the extension line comprisesadditional controller operating parameters and, responsive to theconnection is configured to provide the additional controller operatingparameters to the controller.

In accordance with yet a further feature, the controller operatingparameters comprise a catheter identifier and the controller isconfigured to receive the catheter identifier in the automatic responseto the catheter being operatively connected to at least one of thevacuum source and the controller and, responsive to the connection, tocarry out a pre-determined control pattern associated with the catheteridentifier to change the level of vacuum at the distal end of thecatheter.

In accordance with yet an added feature, the controller is part of thevacuum source and the controller is configured to receive the catheteridentifier in the automatic response to the catheter being operativelyconnected to the vacuum source.

In accordance with yet an additional feature, the controller is separatefrom the vacuum source and the controller is configured to receive thecatheter identifier in the automatic response to the catheter beingoperatively connected to the controller.

In accordance with again another feature, the controller operatingparameters comprise a catheter identifier and the catheter comprises anextension line having a first end connected to the catheter and a secondend connected to at least one of the vacuum source and the controller,comprising the catheter identifier, and, responsive to the connection,the extension line is configured to provide the catheter identifier tothe controller and fluidically connects the proximal end of the catheterwith the vacuum source.

In accordance with again a further feature, the controller is part ofthe vacuum source and the controller is configured to receive thecatheter identifier in the automatic response to the extension linebeing operatively connected to the vacuum source.

In accordance with again an added feature, the controller is separatefrom the vacuum source and the controller is configured to receive thecatheter identifier in the automatic response to the extension linebeing operatively connected to the controller.

In accordance with again an additional feature, the controller isconfigured to repeatedly and periodically carry out the control pattern.

In accordance with still another feature, the controller is one of amechanical valve controller and an electronic valve controller.

In accordance with still a further feature, there is provided a controlelement operatively connected to the controller and, responsive toactuation of the control element, the controller carries out the controlpattern.

In accordance with still an added feature, the controller is part of thevacuum source and the extension line fluidically connects the proximalend of the catheter to the vacuum source or the controller is separatefrom the vacuum source and is removably coupleable to the vacuum sourceand the extension line fluidically connects the proximal end of thecatheter to the controller.

In accordance with still an additional feature, the operative connectionof the catheter to the at least one of the vacuum source and thecontroller is an identification sub-assembly.

In accordance with another feature, the identification sub-assembly isdisposed at the connection between the catheter and the extension line.

In accordance with a further feature, the operative connection of atleast one of the catheter and the extension line to the at least one ofthe vacuum source and the controller is an identification sub-assembly.

In accordance with an added feature, the identification sub-assembly isat least one of an inductive sensor and sensed part, an RFID tag andreader, an NFC tag and reader, a 1-wire detection system, a 2-wiredetection configuration, a Bluetooth low energy device, metallic touchpads, at least one passive resistor configuration, and at least one hallsensor.

In accordance with an additional feature, the identificationsub-assembly is at least one of a manual user interface in which theuser communicates to the controller which controller operatingparameters to use with the catheter, a QR code and a QR code reader inwhich the QR code provided with the catheter communicates to thecontroller which controller operating parameters to use with thecatheter, a bar code and a bar code reader in which the bar codeprovided with the catheter communicates to the controller whichcontroller operating parameters to use with the catheter, and apunch-card and punch-card reader in which the punch-card provided withthe catheter communicates to the controller which controller operatingparameters to use with the catheter.

In accordance with yet another feature, the identification sub-assemblycomprises a reader disposed at least one of at the vacuum source, at thecontroller as part of the vacuum source, and at the controller separablefrom the vacuum source.

In accordance with yet a further feature, the catheter comprises anextension line having a first end connected to the catheter and a secondend opposite the first end and the operative connection of the catheteris an identification sub-assembly comprising a reader disposed at leastone of, at the extension line, at the vacuum source, at the controlleras part of the vacuum source, at the controller separate from the vacuumsource, and at the controller separable from the vacuum source.

In accordance with yet an added feature, a manifold comprising thevacuum modulator and an output and an extension line fluidicallyconnecting the proximal end of the catheter to the output of themanifold.

In accordance with yet an additional feature, there is provided anextension line operatively connected to at least one the vacuummodulator and the controller and fluidically connecting the proximal endof the catheter to at least one the vacuum modulator and the controller.

In accordance with again another feature, the operative connection ofthe catheter to the at least one of the vacuum modulator and thecontroller is an identification sub-assembly.

In accordance with again a further feature, a portion of the controlpattern includes a time period where both the vent and vacuum valves areclosed.

In accordance with again an added feature, the controller is configuredto repeatedly and periodically carry out the control pattern with thevent and vacuum valves.

In accordance with again an additional feature, the controller isconfigured to open and close the vent and vacuum valves in a repeatedcycle comprising a vent-only state in which the vacuum valve is closedand the vent valve is open, and a time of the vent-only state is nogreater than 50 ms.

In accordance with still another feature, the lumen has a diameter ofbetween approximately 0.038″ and approximately 0.106″ and the controlleris configured to repeatedly and periodically carry out the controlpattern of opening and closing the vent and vacuum valves at a frequencyof between approximately 2 Hz and approximately 16 Hz.

In accordance with still a further feature, there is provided anextension line operatively connected to at least one of the vent valve,the vacuum valve, and the controller and fluidically connecting theproximal end of the catheter to at least one of the vent valve, thevacuum valve, and the controller.

In accordance with still an added feature, the operative connection ofthe catheter to the at least one of the vent valve, the vacuum valve,the vacuum source, and the controller is an identification sub-assembly.

In accordance with still an additional feature, the controller operatingparameters comprises catheter identifiers, the catheter is one of aplurality of different catheters each having one of the catheteridentifiers, and the controller is configured to store a plurality ofpre-determined control patterns of opening and closing the vent andvacuum valves, each of the plurality of pre-determined control patternsbeing associated with one of the catheter identifiers and operate thevent and vacuum valves according to the pre-determined control patternassociated with the one catheter identifier in an automatic response toeach of the catheters being operatively connected to the at least one ofthe vent valve, the vacuum valve, the controller, and the vacuum source.

In accordance with still an additional feature, the catheter is one of aplurality of different catheters each having a given set of thecontroller operating parameters and the controller is configured toreceive the given set of the controller operating parameters and operatethe vent and vacuum valves in the control pattern based upon the givenset of controller operating parameters in an automatic response to eachof the catheters being operatively connected to the at least one of thevent valve, the vacuum valve, the controller, and the vacuum source.

In accordance with still an additional feature, the change in the levelof vacuum at the distal end of the catheter is one of greater thanapproximately 15 inHg and occurs in no greater than approximately 50 ms,greater than approximately 20 inHg and occurs in no greater thanapproximately 30 ms, and greater than approximately 25 inHg and occursin no greater than approximately 20 ms.

In accordance with a concomitant feature, the controller is configuredto open and close the vacuum and vent valves in a repeated cycle of thecontrol pattern to retain a level of pressure at the distal end of thecatheter at less than physiological pressure.

Although the systems, apparatuses, and methods are illustrated anddescribed herein as embodied in an aspiration thrombectomy system andmethods for thrombus removal with aspiration catheter, it is,nevertheless, not intended to be limited to the details shown becausevarious modifications and structural changes may be made therein withoutdeparting from the spirit of the invention and within the scope andrange of equivalents of the claims. Additionally, well-known elements ofexemplary embodiments will not be described in detail or will be omittedso as not to obscure the relevant details of the systems, apparatuses,and methods.

Additional advantages and other features characteristic of the systems,apparatuses, and methods will be set forth in the detailed descriptionthat follows and may be apparent from the detailed description or may belearned by practice of exemplary embodiments. Still other advantages ofthe systems, apparatuses, and methods may be realized by any of theinstrumentalities, methods, or combinations particularly pointed out inthe claims.

Other features that are considered as characteristic for the systems,apparatuses, and methods are set forth in the appended claims. Asrequired, detailed embodiments of the systems, apparatuses, and methodsare disclosed herein; however, it is to be understood that the disclosedembodiments are merely exemplary of the systems, apparatuses, andmethods, which can be embodied in various forms. Therefore, specificstructural and functional details disclosed herein are not to beinterpreted as limiting, but merely as a basis for the claims and as arepresentative basis for teaching one of ordinary skill in the art tovariously employ the systems, apparatuses, and methods in virtually anyappropriately detailed structure. Further, the terms and phrases usedherein are not intended to be limiting; but rather, to provide anunderstandable description of the systems, apparatuses, and methods.While the specification concludes with claims defining the systems,apparatuses, and methods of the invention that are regarded as novel, itis believed that the systems, apparatuses, and methods will be betterunderstood from a consideration of the following description inconjunction with the drawing figures, in which like reference numeralsare carried forward.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures, where like reference numerals refer toidentical or functionally similar elements throughout the separateviews, which are not true to scale, and which, together with thedetailed description below, are incorporated in and form part of thespecification, serve to illustrate further various embodiments and toexplain various principles and advantages all in accordance with thesystems, apparatuses, and methods. Advantages of embodiments of thesystems, apparatuses, and methods will be apparent from the followingdetailed description of the exemplary embodiments thereof, whichdescription should be considered in conjunction with the accompanyingdrawings in which:

FIG. 1 is a fragmentary, perspective view of an exemplary embodiment ofa controller for a thrombectomy aspiration catheter in an unactuatedstate;

FIG. 2 is a fragmentary, perspective, longitudinal cross-sectional viewof the controller of FIG. 1;

FIG. 3 is an enlarged, diagrammatic, side elevational view of acompression cam assembly of the controller of FIG. 1;

FIG. 4 is a fragmentary, longitudinal cross-sectional view of thecontroller of FIG. 1 with a compression roller removed;

FIG. 5 is a fragmentary, longitudinal cross-sectional view of thecontroller of FIG. 1 in an actuated state;

FIG. 6 is a fragmentary, enlarged, perspective view of a portion of anextrusion compressor of the controller of FIG. 1;

FIG. 7 is a fragmentary, perspective view of the controller of FIG. 1 inthe actuated state;

FIG. 8 is a fragmentary, perspective and partially longitudinalcross-sectional view of the controller of FIG. 7;

FIG. 9 is a fragmentary, perspective and longitudinal cross-sectionalview of the controller of FIG. 1 in an intermediate actuated state withthe compression roller occluding the aspiration catheter and partiallyrolled to cause fluid column shift;

FIG. 10 is a fragmentary, longitudinal cross-sectional view of thecontroller of FIG.

FIG. 11 is a fragmentary, perspective and longitudinal cross-sectionalview of the controller of FIG. 1 in the actuated state with thecompression roller occluding the aspiration catheter and fully rolled tocause fluid column shift;

FIG. 12 is a fragmentary, longitudinal cross-sectional view of thecontroller of FIG. 11;

FIG. 13 is a longitudinal cross-sectional view of the controller of FIG.9 with the compression roller and the aspiration catheter removed;

FIG. 14 is a fragmentary, perspective and longitudinal cross-sectionalview of the controller of FIG. 1 in the unactuated state anddiagrammatically connected to a distal portion of the aspirationcatheter with a thrombus lodged in a distal opening of a vacuum channel;

FIG. 15 is a fragmentary, perspective and longitudinal cross-sectionalview of the controller of FIG. 12 in the actuated state with the columnshift that distally dislodges the thrombus from the distal opening ofthe vacuum channel;

FIG. 16 is a fragmentary, enlarged, perspective and longitudinalcross-sectional view of a distal portion of the controller of FIG. 1 andan exemplary embodiment of a vacuum booster disposed between thecontroller and a distal extent of the aspiration catheter with thevacuum booster in an energized state;

FIG. 17 is a fragmentary, enlarged, perspective and longitudinalcross-sectional view of the controller and the vacuum booster of FIG. 16with the vacuum booster in a relaxed state;

FIG. 18 is a fragmentary, enlarged, perspective and partiallytransparent view of a proximal portion of the controller of FIG. 1 andan exemplary embodiment of a thrombus trap;

FIG. 19 is a fragmentary, enlarged, perspective view of the controllerand thrombus trap of FIG. 18 with the intermediate shell of the thrombustrap removed;

FIG. 20 is a fragmentary, enlarged, perspective view of the controllerand thrombus trap of FIG. 18;

FIG. 21 is a fragmentary, perspective and longitudinal cross-sectionalview of the controller of FIG. 16, and the thrombus trap of FIG. 18;

FIG. 22 is a fragmentary, longitudinal cross-sectional view of anexemplary embodiment of a volume changing controller;

FIG. 23 is a vacuum circuit diagram of an exemplary embodiment of avacuum booster and vacuum booster control device;

FIG. 24 is a cycle flow diagram of the operation of exemplaryembodiments of the controller with the vacuum booster and the thrombustrap;

FIG. 25 is a perspective view of an automatic aspiration thrombectomysystem to be connected distally to an aspiration catheter and proximallyto vacuum and vent lines and with a cam housing removed;

FIG. 26 is a fragmentary, top plan view of the aspiration thrombectomysystem of FIG. 25 with diagrammatic illustration of the aspirationcatheter and the vacuum and vent lines;

FIG. 27 is an elevational view of a proximal side of the aspirationthrombectomy system of FIG. 25;

FIG. 28 is an elevational view of a bearing side of the aspirationthrombectomy system of FIG. 25;

FIG. 29 is a perspective and longitudinally cross-sectional view of theaspiration thrombectomy system of FIG. 25 with a vacuum valve in aclosed state, a vent valve in an open state, and a flag of a positionalreset assembly in a zero reset state;

FIG. 30 is a longitudinally cross-sectional view of the aspirationthrombectomy system of FIG. 29;

FIG. 31 is an enlarged cross-sectional view of a valve and cam set ofthe aspiration thrombectomy system of FIG. 25 with the cam in arotational position to set an intermediate closing of the valve;

FIG. 32 is an enlarged cross-sectional view of the valve and cam set ofFIG. 31 with the cam in a rotational position to close the valve;

FIG. 33 is a cross-sectional view of the aspiration thrombectomy systemof FIG. 25 along section line 33-33 in FIG. 30 with the cam housingremoved;

FIG. 34 is a perspective view of the aspiration thrombectomy system ofFIG. 25 with the motor assembly housing removed;

FIG. 35 is a top plan view of the aspiration thrombectomy system of FIG.26 with the motor assembly housing removed;

FIG. 36 is an elevational view of the aspiration thrombectomy system ofFIG. 27 with the motor assembly housing removed;

FIG. 37 is an elevational view of the bearing side of the aspirationthrombectomy system of FIG. 28 with the motor assembly housing removed;

FIG. 38 is a perspective view of the aspiration thrombectomy system ofFIG. 25 with the cam housing;

FIG. 39 is a top plan view of the aspiration thrombectomy system of FIG.26 with the cam housing;

FIG. 40 is an elevational view of the aspiration thrombectomy system ofFIG. 27 with the cam housing;

FIG. 41 is an elevational view of the bearing side of the aspirationthrombectomy system of FIG. 28 with the cam housing;

FIG. 42 is a fragmentary, partially hidden, perspective view of anexemplary embodiment of a rotational pintle valve to be employed withthe aspiration thrombectomy system in a first valve state;

FIG. 43 is a fragmentary, cross-sectional view of the valve of FIG. 42;

FIG. 44 is a fragmentary, partially hidden, perspective view of thevalve of FIG. 42;

FIG. 45 is a fragmentary, partially hidden, perspective view of thevalve of FIG. 42 in a second valve state;

FIG. 46 is a fragmentary, cross-sectional view of the valve of FIG. 45;

FIG. 47 is a diagrammatic, cross-sectional view of an exemplaryembodiment of an aspiration thrombectomy system;

FIG. 48 is a graph of an exemplary embodiment of a waveform foroperating the system of FIG. 47 with a ROAR process to quell pressurepulses;

FIG. 49 is a graph illustrating an exemplary embodiment of one cycle ofa waveform operation of a vacuum valve and a vent valve of the system ofFIG. 47;

FIG. 50 is a graph illustrating pressure curves at a proximal portionand a distal portion of a lumen of a catheter of the system of FIG. 47operating with the waveform of FIG. 49,

FIG. 51 is a graph illustrating the waveforms of FIGS. 49 and 50combined together in time;

FIG. 52 is a graph of an exemplary embodiment of a waveform foroperating the system of FIG. 47 with a ROAR process to quell pressurepulses;

FIG. 53 is a graph illustrating positions of the vacuum and vent valvesof the system of FIG. 47 for tuning the valves to create a ROAR effect;

FIG. 54 is a fragmentary, longitudinal cross-sectional view of aproximal manifold connector assembly for the system of FIG. 47;

FIG. 55 is a block diagram of an exemplary embodiment of aself-contained, aspiration thrombectomy system;

FIG. 56 is a block diagram of the system of FIG. 55 with an exemplaryembodiment of a proximal manifold connector assembly having remotecontrols;

FIG. 57 is a perspective view of an exemplary embodiment of aself-contained, aspiration thrombectomy system with a collectioncanister and a vent liquid reservoir indicated diagrammatically;

FIG. 58 is a fragmentary, perspective view of a cassette connectionassembly of the system of FIG. 57;

FIG. 59 is a top plan view of the system of FIG. 57;

FIG. 60 is a left side elevational view of the system of FIG. 57;

FIG. 61 is a right side elevational view of the system of FIG. 57;

FIG. 62 is a perspective view of an exemplary embodiment of aself-contained, aspiration thrombectomy system with a collectioncanister and a hanging vent liquid reservoir indicated diagrammatically;

FIG. 63 is a left side elevational view of the system of FIG. 62;

FIG. 64 is a right side elevational view of the system of FIG. 62;

FIG. 65 is a top plan view of the system of FIG. 62;

FIG. 66 is a front elevational view of the system of FIG. 57;

FIG. 67 is a fragmentary, front perspective view of cassette connectionassembly and the hanging vent liquid reservoir of the system of FIG. 57;

FIG. 68 is a top plan view of an exemplary embodiment of a valvecassette for the systems of FIGS. 57 to 67 with hidden line views offluid lumens;

FIG. 69 is a bottom plan view of the valve cassette of FIG. 69;

FIG. 70 is a bottom perspective view of the valve cassette of FIG. 69;

FIG. 71 is a bottom perspective view of the valve cassette of FIG. 69;and

FIG. 72 is a diagrammatic illustrated of an exemplary embodiment of aself-contained, aspiration thrombectomy system.

DETAILED DESCRIPTION

As required, detailed embodiments of the systems, apparatuses, andmethods are disclosed herein; however, it is to be understood that thedisclosed embodiments are merely exemplary of the systems, apparatuses,and methods, which can be embodied in various forms. Therefore, specificstructural and functional details disclosed herein are not to beinterpreted as limiting, but merely as a basis for the claims and as arepresentative basis for teaching one skilled in the art to variouslyemploy the systems, apparatuses, and methods in virtually anyappropriately detailed structure. Further, the terms and phrases usedherein are not intended to be limiting; but rather, to provide anunderstandable description of the systems, apparatuses, and methods.While the specification concludes with claims defining the features ofthe systems, apparatuses, and methods that are regarded as novel, it isbelieved that the systems, apparatuses, and methods will be betterunderstood from a consideration of the following description inconjunction with the drawing figures, in which like reference numeralsare carried forward.

In the following detailed description, reference is made to theaccompanying drawings which form a part hereof, and in which are shownby way of illustration embodiments that may be practiced. It is to beunderstood that other embodiments may be utilized and structural orlogical changes may be made without departing from the scope. Therefore,the following detailed description is not to be taken in a limitingsense, and the scope of embodiments is defined by the appended claimsand their equivalents.

Alternate embodiments may be devised without departing from the spiritor the scope of the invention. Additionally, well-known elements ofexemplary embodiments of the systems, apparatuses, and methods will notbe described in detail or will be omitted so as not to obscure therelevant details of the systems, apparatuses, and methods.

Before the systems, apparatuses, and methods are disclosed anddescribed, it is to be understood that the terminology used herein isfor the purpose of describing particular embodiments only and is notintended to be limiting. The terms “comprises,” “comprising,” or anyother variation thereof are intended to cover a non-exclusive inclusion,such that a process, method, article, or apparatus that comprises a listof elements does not include only those elements but may include otherelements not expressly listed or inherent to such process, method,article, or apparatus. An element proceeded by “comprises . . . a” doesnot, without more constraints, preclude the existence of additionalidentical elements in the process, method, article, or apparatus thatcomprises the element. The terms “including” and/or “having,” as usedherein, are defined as comprising (i.e., open language). The terms “a”or “an”, as used herein, are defined as one or more than one. The term“plurality,” as used herein, is defined as two or more than two. Theterm “another,” as used herein, is defined as at least a second or more.The description may use the terms “embodiment” or “embodiments,” whichmay each refer to one or more of the same or different embodiments.

The terms “coupled” and “connected,” along with their derivatives, maybe used. It should be understood that these terms are not intended assynonyms for each other. Rather, in particular embodiments, “connected”may be used to indicate that two or more elements are in direct physicalor electrical contact with each other. “Coupled” may mean that two ormore elements are in direct physical or electrical contact (e.g.,directly coupled). However, “coupled” may also mean that two or moreelements are not in direct contact with each other, but yet stillcooperate or interact with each other (e.g., indirectly coupled).

For the purposes of the description, a phrase in the form “A/B” or inthe form “A and/or B” or in the form “at least one of A and B” means(A), (B), or (A and B), where A and B are variables indicating aparticular object or attribute. When used, this phrase is intended toand is hereby defined as a choice of A or B or both A and B, which issimilar to the phrase “and/or”. Where more than two variables arepresent in such a phrase, this phrase is hereby defined as includingonly one of the variables, any one of the variables, any combination ofany of the variables, and all of the variables, for example, a phrase inthe form “at least one of A, B, and C” means (A), (B), (C), (A and B),(A and C), (B and C), or (A, B and C).

Relational terms such as first and second, top and bottom, and the likemay be used solely to distinguish one entity or action from anotherentity or action without necessarily requiring or implying any actualsuch relationship or order between such entities or actions. Thedescription may use perspective-based descriptions such as up/down,back/front, top/bottom, and proximal/distal. Such descriptions aremerely used to facilitate the discussion and are not intended torestrict the application of disclosed embodiments. Various operationsmay be described as multiple discrete operations in turn, in a mannerthat may be helpful in understanding embodiments; however, the order ofdescription should not be construed to imply that these operations areorder dependent.

As used herein, the term “about” or “approximately” applies to allnumeric values, whether or not explicitly indicated. These termsgenerally refer to a range of numbers that one of skill in the art wouldconsider equivalent to the recited values (i.e., having the samefunction or result). In many instances these terms may include numbersthat are rounded to the nearest significant figure. As used herein, theterms “substantial” and “substantially” means, when comparing variousparts to one another, that the parts being compared are equal to or areso close enough in dimension that one skill in the art would considerthe same. Substantial and substantially, as used herein, are not limitedto a single dimension and specifically include a range of values forthose parts being compared. The range of values, both above and below(e.g., “+/−” or greater/lesser or larger/smaller), includes a variancethat one skilled in the art would know to be a reasonable tolerance forthe parts mentioned.

It will be appreciated that embodiments of the systems, apparatuses, andmethods described herein may be comprised of one or more conventionalprocessors and unique stored program instructions that control the oneor more processors to implement, in conjunction with certainnon-processor circuits and other elements, some, most, or all of thefunctions of the systems, apparatuses, and methods described herein. Thenon-processor circuits may include, but are not limited to, signaldrivers, clock circuits, power source circuits, and user input andoutput elements. Alternatively, some or all functions could beimplemented by a state machine that has no stored program instructions,or in one or more application specific integrated circuits (ASICs) orfield-programmable gate arrays (FPGA), in which each function or somecombinations of certain of the functions are implemented as customlogic. Of course, a combination of these approaches could also be used.Thus, methods and means for these functions have been described herein.

The terms “program,” “software,” “software application,” and the like asused herein, are defined as a sequence of instructions designed forexecution on a computer system or programmable device. A “program,”“software,” “application,” “computer program,” or “software application”may include a subroutine, a function, a procedure, an object method, anobject implementation, an executable application, an applet, a servlet,a source code, an object code, any computer language logic, a sharedlibrary/dynamic load library and/or other sequence of instructionsdesigned for execution on a computer system.

Herein various embodiments of the systems, apparatuses, and methods aredescribed. In many of the different embodiments, features are similar.Therefore, to avoid redundancy, repetitive description of these similarfeatures may not be made in some circumstances. It shall be understood,however, that description of a first-appearing feature applies to thelater described similar feature and each respective description,therefore, is to be incorporated therein without such repetition.

Described now are exemplary embodiments. Referring now to the figures ofthe drawings in detail and first, particularly to FIGS. 1 to 13, thereis shown a first exemplary embodiment of a one-handed controller 10 foran aspiration thrombectomy system 1 utilizing a vacuum tube 2. Thecontroller 10 comprises a first handle part 20 and a second handle part40. The first handle part 20 is connected to and holds the vacuum tube 2and, therefore, is also referred to as a handle base. The second handlepart 40 moves with respect to the first handle part 20 and, therefore,the second handle part 40 is also referred to as a compressor-actuator40.

In an exemplary embodiment, the first handle part 20 has a distal tubeanchor 22 and a proximal tube anchor 24. In this embodiment, the distaland proximal tube anchors 22, 24 are in the form of hollow tubes throughwhich the vacuum tube 2 traverses. The distal and proximal tube anchors22, 24 hold the vacuum tube 2 therein substantially without compressingthe vacuum tube 2 (and thereby does not reduce or close the inner vacuumchannel 3). The vacuum tube 2 can be of many materials, including latex,silicone, Pebax®, polyurethane, polyvinyl chloride, or other syntheticrubber. Exemplary sizes for the vacuum tube 2 have an inner diameter(I.D.) of approximately 0.055 to 0.095 inches. One exemplary embodimentfor retaining the vacuum tube 2 is an adhesive that bonds the materialof the vacuum tube 2 to the interior lumens of the tubular tube anchors22, 24. In this exemplary embodiment, the vacuum tube 2 is fixed to thefirst handle part 20. In an alternative embodiment, the first handlepart 20 is a clamshell having two first handle part halves (notillustrated) that open to receive the cylindrical vacuum tube 2 and,when closed thereupon, the tube anchors 22, 24 tightly grip the vacuumtube 2 therein substantially without closing or occluding the vacuumchannel 3 of the vacuum tube 2. In one exemplary clamshell embodiment,the first handle part 20 is split horizontally at the dashed line inFIG. 2 with a hinge, allowing a portion of the vacuum tube 2 to beinserted into and removed from the distal and proximal tube anchors 22,24. A lock secures the vacuum tube 2 therein until the user desiresremoval. The hinge is useful to allow the surgeon to reposition thecontroller 10 along the vacuum tube 2.

The exemplary embodiment of the distal and proximal tube anchors 22, 24are separated from one another over a distance. Between the distal andproximal tube anchors 22, 24 of the first handle part 20 is acompression floor 26. When installed within the first handle part 20,the vacuum tube 2 lays against the compression floor 26 between thedistal and proximal tube anchors 22, 24 substantially without closing oroccluding the vacuum channel 3. FIG. 13 illustrates the compressionfloor 26 of first handle part 20 with the vacuum tube 2 removed.

The first handle part 20 has a hollow interior that defines a set ofparallel lateral walls 32 on either side of the vacuum tube 2. The firsthandle part 20 comprises a compression cam assembly 30 that permits thesecond handle part 40 to move in two directions with respect to thefirst handle part 20. More specifically, in the exemplary embodiment,the compression cam assembly 30 comprises a set of slots 34 formed inthe lateral walls 32 of the first handle part 20. As shown in theenlarged view of FIG. 3, these slots 34 have a vertical extent 35 and anangled extent 36. The vertical extent 35 has a vertical length and theangled extent 36 has a vector length that is comprised of a secondvertical extent 37 and a horizontal extent 39. Accordingly, as explainedbelow, the slots 34 provide a cam surface for movement of the secondhandle part 40 in the same shape as the slot 34.

In the exemplary embodiment, to contact the first and second handleparts 20, 40 together, the second handle part 40 has a hollow interiorinto which the first handle part 20 is inserted and projects. (In analternative embodiment, the first handle part 20 has a hollow interiorinto which the second handle part 40 is inserted and projects.) A widthbetween interior facing lateral surfaces of the hollow compartment ofthe second handle part 40 is approximately equal to the width of theexterior surfaces of the lateral walls 32 such that the second handlepart 40 can move up and down on the first handle part 20 tightly butsmoothly with little or substantially no friction. In comparison, thelength between interior facing longitudinal surfaces of the hollowcompartment of the second handle part 40 is greater than the length ofthe exterior surfaces of the longitudinal walls 38. The difference inlength is sufficiently long enough to allow the second handle part 40 tomove along the horizontal extent 39 longitudinally parallel with thevacuum tube 2 throughout the horizontal extent 39.

Movement of the compressor-actuator 40 with respect to the handle base20 follows the slots 34 by providing the compressor-actuator 40 withbosses 42 protruding from the interior facing surfaces of the lateralwalls 42 of the hollow compartment of the compressor-actuator 40; onecircular boss 42 is associated with each of the slots 34. In this way,movement of the compressor-actuator 40 is guided by and restricted bythe shape of the slots 34. In an unactuated state of the controller 10,shown in FIGS. 1, 2, and 4, the bosses 42 reside at the end of thevertical extent 35, which in the exemplary embodiment is at theuppermost end of the slot 34. (It is noted that the embodiment shown inFIGS. 1 to 13 provide four slots 34 and four bosses 42. This number ismerely exemplary. The cam surface of the slots 34, the extents 35, 36 ofthe slots 34, and the cam follower of the bosses 42 can take any form orshape that causes the controller to operate as described herein.) Asseen most clearly in FIG. 4, a distance A between an interior of theproximal longitudinal wall 38 of the compressor-actuator 40 and anexterior of the proximal wall of the first handle part 20 is longer thanthe horizontal extent 39 (i.e., 1A1>1391). When the compressor-actuator40 is fully actuated as shown in FIG. 5, the bosses 42 travel to theopposite (lowermost) end of the slot 34. The compressor-actuator 40,therefore, has traveled a vertical distance equal to the verticalmovement of the bosses 42 within the vertical and angled extents 35, 36and has traveled a horizontal distance equal to the horizontal extent39. The exemplary embodiments of the first and second handle parts 20,40 have the interior surface of the distal longitudinal wall of thecompressor-actuator 40 touching the exterior surface of the distallongitudinal wall of the handle base 20, this touch being indicated witharrows B in FIG. 4 (i.e., 1B1=0). When the compressor-actuator 40 isfully actuated, therefore, these two distal longitudinal walls separateto a distance equal to the horizontal extent 39. Likewise, the distancebetween an exterior surface of the proximal longitudinal wall of thehandle base 20 and an interior surface of the proximal longitudinal wallof the compressor-actuator 40 shortens from A by a length equal to thehorizontal extent 39 (i.e., (A-1391)), which is illustrated in FIG. 5.Alternately, a four-bar linkage could be provided to join 20 and 40 tocreate the same motion as the cam slots and bosses.

What becomes apparent from movement of the compressor-actuator 40following the slots 34 is how an extrusion compressor 50 connected tothe compressor-actuator 40 operates during this movement. The exemplaryembodiment of the extrusion compressor 50 in FIGS. 1, 2 and 4 to 13 hasthe extrusion compressor 50 project from an interior surface of aceiling of the hollow compartment of the compressor-actuator 40downwards towards the handle base 20. In particular, the extrusioncompressor 50 projects downwards towards the compression floor 26 of thehandle base 20. The extrusion compressor 50 has a base 52 attached tothe second handle part 40. A flex arm 54 projects from the base 52 andextends towards the compression floor 26. In the exemplary embodiment,the flex arm 54 is thinner than the base 52. A material from which thebase 52 and flex arm 54 are made is not substantially rigid and,therefore, responsive to moving downwards to have a portion of theextrusion compressor 50 touch the compression floor 26 before the entirevertical movement of the compressor-actuator 40 is complete, the flexarm 54 flexes. Example materials for the base 52 and flex arm 54 includeABS, polycarbonate and Nylon®, polypropylene, polyurethane, or otherthermoplastic or thermoplastic elastomer and/or fiber filled ABS,polycarbonate and Nylon®. At a distal end of the flex arm 54 is a gearflange 56 shaped to hold thereat a compression roller 60. The gearflange 56 has axle ports in which an axle 62 of the compression roller60 resides. When installed between the interior sides of the gear flange56, the compression roller 60 becomes fixed to the gear flange 56 in alldirections except for rotational movement of the compression roller 60about a rotation axis 64 of the roller 60; in other words, the roller 60is allowed to rotate about the axis 64.

It is noted that the extrusion compressor 50 shown is an exemplaryembodiment. Different mechanical structures performing the same functioncan be used. For example, the base 52 and flex arm 54 can be replacedwith a single beam that is hinged to the ceiling of the interior hollowof the compressor-actuator 40 and biased with a bias device (e.g., aspring) towards the compression floor 26 such that the point of thecompression roller 60 touches the vacuum tube 2 as shown in FIG. 2enough to grip the vacuum tube 2 but substantially not reduce thecross-sectional area of the vacuum channel 3.

Rotation of the roller 60 is dependent upon how the roller 60 movestowards the vacuum tube 2 and along the vacuum tube 2. In this regard,the compression roller 60 has an exterior contact surface 66 thatcontacts the vacuum tube 2 in various ways when the compressor-actuator40 is moved towards the handle base 20. As shown in FIG. 6, alongitudinal cross-section of the exterior surface 66 is approximatelyin the shape of a nautilus (alternatively, the shape can becylindrical). The exterior surface 66 has a contact point 67, which isin contact with the exterior surface of the vacuum tube 2 in theunactuated state of the compressor-actuator 40 as shown in FIG. 2 (thevacuum channel 3 is unoccluded with a substantially patent and opencross-section). As the compressor-actuator 40 is actuated, thecompressor-actuator 40 travels along the vertical extent 35. This movesthe contact point 67 towards the compression floor 26. When thecompressor-actuator 40 has travelled along the entirety of the verticalextent 35, as shown in FIGS. 7 and 8, the contact point 67 has movedagainst the vacuum tube 2 to occlude the vacuum channel 3 completely. Atthe stage where the bosses 42 are at this transition point from thevertical extent 35 to the angled extent 36, the contact point 67 is asfar towards the compression floor 26 as it can move in thatdirection—because the thickness of the vacuum tube 2 prevents furthermovement of the contact point 67 towards the compression floor 26.

In a procedure where the vacuum tube 2 is used in a thrombectomy, thevacuum channel 3 will be filled with a fluid, i.e., blood. When thevacuum channel 3 is completely occluded, the blood that fills up thevacuum channel 3 from the contact point 67 of the compression roller 60distally to the distal end of the vacuum channel 3 defines a column offluid, which fluid is not compressible. The controller 10 is configuredto apply the extrusion compressor 50 and the compression roller 60 tomove this column of fluid a shift distance 70 in the distal direction.An exemplary volume of the shift distance is approximately 0.001 ml toapproximately 1.0 ml, in particular, approximately 0.1 ml toapproximately 0.5 ml. An exemplary length of the shift distance 70 isapproximately 0.5 mm to approximately 30 mm, in particular,approximately 0.5 mm to approximately 15 mm. To effect such a movement,the compressor-actuator 40 is moved further in the direction towards thehandle base 20, which means that that the bosses 42 travel along andthrough to the end of the angled extent 36. Because the contact point 67is already as far towards the compression floor 26 as it can move inthat direction (i.e., when the bosses 42 are at the transition pointfrom the vertical extent 35 to the angled extent 36), the extrusioncompressor 50 has no other way to move than to flex the flex arm 54and/or to roll the compression roller 60. The contact surface 66 of thecompression roller 60 is shaped to roll (counterclockwise in the viewsof FIGS. 2 and 8 to 12) against an upper surface of the vacuum tube 2.FIGS. 9 and 10 illustrate the rolling start of the compression roller 60at a point where the bosses 42 are approximately halfway to the distalend of the slot 34 within the angled extent 36. (It is noted thatlimitation of the computer software that generates FIGS. 9 to 12 do notallow for displaying a realistic view of how the vacuum tube 2compresses as the compression roller 60 rotates. These figures,therefore, illustrate an approximation of the compression roller 60rolling on and over the shift distance 70 of the vacuum tube 2.) Thecontact point 67 of the compression roller 60 is offset from therotation axis 64 towards the contact surface 66. This forms an overcenter, or toggle, such that the initial rolling motion of thecompression roller must first force the contact point 67 over the centerof the rotation axis 64. In such a configuration, not only does thecompression roller 60 roll once the bosses 42 of thecompression-actuator 40 start traveling in the angled extent 37, butthere is also a tactile feedback transmitted to the compression-actuator40 once the axle 62 moves slightly forward. This feedback, when felt bythe user, indicates to the user that the contact surface 66 of thecompression roller 60 has rolled onto a portion of the vacuum tube 2and, as it moves along the vacuum tube 2, squeezes that portion totranslate the fluid column in the distal direction of the vacuum tube 2.With complete movement of the compression-actuator 40 towards the handlebase 20 as shown in FIGS. 11 and 12, the compression roller 60 hascompleted its defined rotation over the vacuum tube 2 and, in doing so,has squeezed a segment of the vacuum channel 3 from proximal to distalover the length to shift the fluid column distally to a length equal tothe shift distance 70.

To return the controller 10 to the initial, unactuated state shown inFIGS. 1 and 2, for example, a bias device 12 is interposed between anysurface of the interior hollow of the compression-actuator 40 and anysurface of interior hollow of the handle base 20. In the exemplaryembodiment shown in FIGS. 2 and 8, the bias device 12 is disposedbetween the surface of the ceiling within the interior hollow of thecompression-actuator 40 and an upper surface of the proximal tube anchor24. This configuration for the bias device 12 is merely exemplary andany return spring or similar mechanical device can be placed and used.When the user releases pressure on the compression-actuator 40, the flexarm 54 and/or the bias device 12 causes the compression-actuator 40 toreturn to the initial, unactuated state. This action rolls thecompression roller 60 in the opposite direction (i.e., the progressionfrom FIG. 11 to FIG. 9 to FIG. 8). As the distal end of the vacuumchannel 3 experiences positive pressure from the patient and also fromthe increase in volume as the crushed tube rebounds, the fluid columnretreats proximally back into the vacuum channel 3 and, when thecompression roller 60 releases from the vacuum tube 2 to cease occludingthe vacuum channel 3, vacuum being placed in the vacuum channel 3 from avacuum pump 80 proximal to the controller 10 automatically reestablishesand draws the fluid column through the segment of the vacuum tube 2within the controller 10.

As set forth herein, the vacuum tube 2 is sized to lay against thecompression floor 26 on one side and to have the point of thecompression roller 60 touch the outer surface of the vacuum tube 2 justslightly enough to grip the vacuum tube 2 but substantially not reducethe cross sectional area of vacuum channel 3. In an embodiment where thevacuum tube 2 is not fixed within the handle base 20, the compressionroller 60 is provided with a non-illustrated bias device that biases thecompression roller 60 rotationally into a position shown in FIG. 2. Thisbias compensates in a situation where the vacuum tube 2 is not touchingthe compression roller in the unactuated position of thecompressor-actuator 40.

With a configuration as described, the controller 10 is to be used witha vacuum tube 2 that is or is part of a thrombectomy aspirationcatheter. Such use is described with regard to FIGS. 14 and 15, in whichthe vacuum lumen 3 is shown as being an aspiration controller that,distal to the controller 10, is threaded through vasculature and up to athrombus 4, which in the form of a blood clot, that has corked within orat the distal opening of the vacuum channel 3. On the proximal side ofthe controller 10, the vacuum channel 3 is fluidically connected to thevacuum pump 80. As indicated above, thrombi typically are trapped at theend of an aspiration catheter and removing the entire catheter from thepatient when that occurs is not desirable. The inventors have discoveredthat removal of the catheter can be prevented using the controller 10.More particular, when the distal end of the vacuum tube 2 is clogged bya thrombus, the controller 10 is actuated to occlude all flow throughthe vacuum channel 3. This occurs by the first movement of thecompressor-actuator 40 towards the handle base 20. The controller 10 isactuated to cause the fluid column to shift distally to the shiftdistance 70. This imparts a controlled reversal of flow to the fluidcolumn within the vacuum channel 3 that slightly translates the thrombusto a prescribed shift distance 70 distally relative to the distalopening of the vacuum channel 3. During a third and final phase, theuser releases actuation of the controller 10 to reset the fluid columnwithin the vacuum channel 3 and, once again, allows the fluid to flowfreely. The inventors have discovered that such movement causes either arepositioning of the thrombus or a deformation of the thrombus or bothand that this movement allows the thrombus to pass entirely into andthrough the vacuum channel 3 where such passage was not possible before.

Operation of the controller 10 is explained with regard to the systemcycle diagram of FIG. 24.

-   -   State 1: Normal aspiration is occurring. The vacuum channel 3 is        not occluded. The controller 100 is in a rest state where the        vacuum pump 80 is connected to the vacuum channel 3.    -   Transition A—Occlusion: Thrombus 4 occludes distal end of vacuum        channel 3. Unclogging controller 10 actuates to occlude vacuum        channel 3 and stop vacuum flow distal of the controller 10.    -   State 2: Flow through the vacuum channel 3 has stopped.    -   Transition B—Unclogging: Controller 10 continues actuation to        cause reverse flow in vacuum channel 3 for a metered volumetric        column shift.    -   State 3: Flow reversal stops.    -   Transition C—Return Column Shift: Controller 10 is reversed to        return column and accelerate thrombus 4 into catheter tip by        reconnecting the vacuum pump 80 to the vacuum channel 3.    -   Return to State 1 and Repeat: Normal aspiration occurs.

The inventors further discovered that greater accelerations of thethrombus into the catheter provide proportionally quicker aspirations. Amagnitude of the thrombus' impact velocity, and therefore its kineticenergy, when it impacts the aspiration catheter's distal tip, affectsthe amount of the thrombus that is deformed to fit within the diameterof the vacuum channel 3. When a catheter is extended to a thrombus thatis lodged in a vessel, e.g., a vessel within the brain, the controller10 is not needed until the thrombus 4 is stuck at the distal opening ofthe vacuum channel 3. Thus, the thrombus does not have any distance tomove in order to accelerate towards the opening of the vacuum channel 3.Imparting the shift distance to the thrombus as described maximizes thekinetic energy of the thrombus at the point when it impacts thecatheter's tip. The thrombus' acceleration (and therefore its kineticenergy) are generated by a pressure differential between intracranialpressure and the effective aspiration pressure at the catheter's tip.For the thrombus to accelerate, both it and the fluid column within thecatheter system must attain a velocity. After catheters are occluded,the fluid velocity within the catheter is substantially zero. Inconventional catheter architecture, the pressure that attempts toaccelerate this fluid column is provided solely by an external vacuumpump. Significantly, however, this pressure is reduced by head losses inthe tubing connecting the vacuum pump to the catheter's proximal end.Accordingly, conventional catheters must be fished out of thevasculature entirely because the thrombus is corked within the distalopening of the vacuum channel.

This disadvantage is removed by the controller 10. After the distalopening of the vacuum channel 3 is occluded by the thrombus, the fluidvelocity within the catheter is substantially zero. The controller 10 isused to unclog the vacuum channel 3 and displace the thrombus 4 distallyout from the distal opening. Then, the controller 10 re-applies vacuum.Upon re-application of vacuum, the fluid column accelerates and thethrombus 4 accelerates back into the vacuum channel 3. With suchacceleration, the thrombus is deformed to a diameter allowing it to beaspirated. With one or just a few applications to displace the thrombusby the shift distance 70 with the controller 10, the vacuum channel 3becomes unclogged and the thrombus 4 accelerates sufficiently to becompletely aspirated through and out of the vacuum tube 2. With thecontroller 10, the head losses in the tubing are minimized, therebyallowing the thrombus to accelerate to a much greater extent than inconventional product architectures.

Realizing that acceleration of the thrombus proximally is a desirabletrait, it becomes possible to enhance acceleration in the proximaldirection when deactuation of the controller 10 occurs to re-establishvacuum. To maximize the acceleration of the thrombus and the fluidcolumn within the vacuum channel 3 for the purpose of maximizing thethrombus' kinetic energy upon its impact with the distal tip of thevacuum tube 2, a vacuum booster 100, illustrated in FIG. 16, isfluidically connected to the vacuum channel 3 of the vacuum tube 2. Ingeneral, the vacuum booster 100 applies suction to the fluid column in aregion of the aspiration catheter's proximal end to maximizeacceleration of the catheter's fluid column at a user-selected time.This exemplary embodiment of the vacuum booster 100 comprises a boosterbody 110 defining a plunger bore 112, a plunger 120 housed within thebore 112, and a bias device 130. The plunger bore 112 is shaped todefine a vacuum chamber 114 and an ambient chamber 116. In the exemplaryembodiment, the vacuum chamber 114 is cylindrical and has a first innerdiameter and the ambient chamber 116 is cylindrical and has a secondinner diameter larger than the first inner diameter. The vacuum chamber114 has a volume that is smaller than a volume of the ambient chamber116.

The plunger 120 has a vacuum piston 122 and an ambient piston 124, whichis connected to the vacuum piston 122 through a rod 123. In theexemplary embodiment, the vacuum piston 122 has a diameter substantiallyequal to the first inner diameter of the vacuum chamber 114 and is ableto move within the vacuum chamber 114. The ambient piston 124 has adiameter substantially equal to the second inner diameter of the ambientchamber 116 and is able to move within the ambient chamber 116. Betweenthe vacuum piston 122 and the ambient piston 124 is a pressure chamber118 in which is located the rod 123 connecting the two pistons 122, 124together, for example, in the shape of an asymmetric dumbbell. To sealthe pressure chamber 118 off from both the vacuum chamber 114 and theambient chamber 116, a vacuum seal 126 is disposed between the vacuumpiston 112 and the wall of the vacuum chamber 114 and an ambient seal128 is disposed between the ambient piston 124 and the wall of theambient chamber 116. The booster body 110 defines the pressure chamber118 and a pressure port 119 that fluidically connects the pressurechamber 118 to a boost control valve or switch 150. This connection isillustrated diagrammatically in FIG. 23.

The vacuum chamber 114 operatively communicates with the vacuum channel3 at a connection 140. The plunger 120 and the bias device 130 aredisposed such that, when the bias device 130 is in a relaxed state, thevacuum piston 122 is at a given distance from the connection 140 to thevacuum channel 3; this relaxed state is illustrated in FIG. 17. In therelaxed state, the spring is at a steady state—there is no potentialenergy stored in the spring. With regard to pressure, in the relaxedstate, both the pressure chamber 118 and the ambient chamber 116 are atambient pressure, i.e., they are substantially equal. When the plunger120 is moved towards the vacuum channel 3 into an energized state (whichis shown in FIG. 16), the bias device 130 (e.g., in the form of a springthat is stretched) thereby stores strain energy that is directed to movethe plunger 120 away from the connection 140. Such movement, when itoccurs, creates suction within the vacuum chamber 114 and the vacuumchannel 3 that communicates with the vacuum chamber 114.

To actuate the embodiment of the pneumatically actuated vacuum booster100, the pressure chamber 118 is connected to the vacuum pump 80 (thevacuum source) through a relatively high impedance conduit 152. Thepressure chamber 118 is also connected to the boost control valve 150,which is connected to ambient pressure but is normally open to preventflow from the pressure chamber 118 to the environment (Patm). When thevacuum booster 100 is in a cocked state (FIG. 16), the boost controlvalve 150 is open (as shown) and, as such, the vacuum pump 80 is able tosignificantly lower pressure within the pressure chamber 118. When theboost control valve 150 is actuated (i.e., connecting the pressurechamber 118 to the ambient environment), pressure equalization occursbetween the pressure chamber 118 and the ambient chamber 116. Animpedance of a connection between the pressure chamber 118 and the boostcontrol valve 150 is designed to be substantially less than theimpedance between the pressure chamber 118 and the vacuum pump 80 suchthat, upon actuation of the boost control valve 150 (i.e., closure),rapid pressure equalization is possible.

Operation of the vacuum booster 100 is explained with regard to thesystem cycle diagram of FIG. 24.

-   -   State 1: Normal aspiration is occurring. The vacuum channel 3 is        not occluded. The controller 100 is in a rest state where the        vacuum pump 80 is connected to the vacuum channel 3. The vacuum        booster 100 is in the cocked state. The thrombus trap 200 is        operating without bleed purge.    -   Transition A—Occlusion: Thrombus 4 occludes distal end of vacuum        channel 3. Unclogging controller 10 actuates to occlude vacuum        channel 3 and stop vacuum flow distal of the controller 10.    -   State 2: Flow through the vacuum channel 3 has stopped.    -   Transition B—Unclogging: Controller 10 continues actuation to        cause reverse flow in vacuum channel 3 for a metered volumetric        column shift.    -   State 3: Flow reversal stops.    -   Transition C—Vacuum Boost: Vacuum booster 100 actuated to        re-initiate flow in nominal direction and accelerate thrombus 4        into catheter tip. Shortly before, at the same time, or shortly        thereafter, controller 10 opens vacuum channel 3 to reinitiate        vacuum of pump 80 for fluid flow and aspiration of thrombus 4        into thrombus trap 200. Simultaneously or thereafter, controlled        purging or automatic purging of thrombus trap 200 occurs        allowing inspection of thrombus 4.    -   Return to State 1 and Repeat: Vacuum booster 100 and        self-purging trap 200 are de-actuated. Normal aspiration occurs.

During the occlusion and column shift phases in the operation of thecontroller 10, the plunger 120 is held in the energized state, with theplunger 120 raised to place the vacuum piston 122 closer to theconnection 140. During or immediately upon the end of the reversalphase, the plunger 120 is released, generating suction within thelocally communicating lumen of the vacuum channel 3 and therebyaccelerating the fluid column proximally in the vacuum direction. Whatfluid is begin drawn into or towards the vacuum chamber has an effect onthe efficiency of the vacuum booster 100. More specifically, if thefluid arrives only from downstream of the vacuum booster 100 whenactuated, then the fluid column will not accelerate proximally asdesired. When the controller 10 occludes the vacuum channel 3, fluidinto and towards the vacuum chamber 114 will arrive substantially fromupstream of the vacuum channel 3, thereby accelerating the fluid columnin the desired direction. In an intermediate stage where fluid arrivesfrom both upstream and downstream, the downstream portion can belimited, for example, by placing a non-illustrated check valve betweenthe thrombus trap 200 and the connection 140, in particular, between theconnection 140 and the controller 10. The check valve can be external orcan use the occlusive function of unclogging handle.

The following description summarizes the forces in a pneumaticembodiment of the vacuum booster 100. In an un-cocked state of theplunger 120, the pressure chamber 118 and the ambient chamber 116 are atambient pressure and the bias device 130 is in substantially in therelaxed state, storing little or no strain energy. In a cocked state ofthe plunger 120, the pressure chamber 118 is caused by the boost controlvalve 118 to be at a significantly lower pressure than the ambientchamber 116. The geometries of the chambers 114, 116, 118 and thepistons 122, 124, and the characteristics of the bias device 130 areselected such that, in this configuration, a force created by thepressure difference across the ambient (larger) piston is significantlygreater than the force required to expand the spring. As such, when thegiven pressures are held, the piston and spring system translatesupwards into a “cocked” position. When the vacuum booster 100 isactuated, the pressure chamber 118 is allowed to rapidly equalize toambient pressure. With no net force input from the ambient piston 124(the larger of the two pistons), any motion of the piston and springsystem are now caused by the actions of the bias device 130 and thepressure differential across the smaller, vacuum piston 122. Thegeometries of the chambers 114, 116, 118 and the pistons 122, 124, andthe characteristics of the bias device 130 are selected such that thebias device's restoring force in the cocked configuration is much higherthan an opposing force caused by the pressure difference across thesmaller vacuum piston 122, which is disposed between ambient pressureand a pressure within the vacuum channel 3. As such, when the vacuumbooster 100 is actuated and the pressure chamber 118 is allowed toequalize to ambient pressure, the piston and spring system energeticallydrives “downwards”, generating a negative displacement and a dramaticpressure decrease within the vacuum chamber 114 and thereby the vacuumchannel 3 of the aspiration device.

As indicated herein, current thrombus removal devices are not able toinform the surgeon that the thrombus has been removed without fullwithdrawal of the device from a patient's anatomy. Surgeons do not havean ability to view the reservoirs into which aspirated contents aredeposited, not only because the reservoirs are located outside of thesterile field in an operating room setting, but also because the removedthrombus is present within a significant quantity of blood contained inthe reservoir.

To overcome an inability to visualize the thrombus actually retrieved, avisualization-aiding thrombus trap 200 is provided and shown in FIGS. 18to 21. The thrombus trap 200 is placed in-line with the aspirationsystem, in particular, the vacuum channel 3. In the exemplaryembodiment, the thrombus trap 200 is within the catheter operator'simmediate vicinity between the aspiration catheter and the vacuumsource, in particular, between the controller 10 and the vacuum pump 80,so that the surgeon can see the thrombus trap 200 during use of thecontroller 10. In use, all aspirated material flows through the thrombustrap 200.

The thrombus trap 200 comprises a container having an inflow section 210having an input orifice 212 fluidically connected to the vacuum channel3, a transparent intermediate trap section 220 in which the thrombus istrapped, and an outflow section 230 fluidically connected to the vacuumpump 80. In operation, aspirated material and fluid travel from thevacuum channel 3 past the controller 10 through the inflow section 210and into the trap section 220. The trap section 220 contains a trapfilter 222 that is, in an exemplary embodiment, a screen or a filterthrough which all aspirated flow must pass. The filter 222 is configuredto stop and capture thrombus material therein but allow the passage ofair and fluid with minimal impedance therethrough and, thereby out ofthe outflow section 230 to the vacuum pump 80 and any associated vacuumpump reservoir 82. In the exemplary embodiment of FIGS. 18 to 22, thefilter 222 is in the form of a grating or screen having orificessufficiently large enough for fluid and air to pass therethrough butsufficiently small enough to substantially prevent the thrombus frompassing across the filter 222 from an inflow or trap chamber 224 of thetrap section 220 to an outflow chamber 226 of the trap section 220. Asused herein, the term “filter” includes any structure that is able toseparate fluid from particulate matter by allowing the fluid to passthrough the structure while preventing the particular matter frompassing through. Other exemplary embodiments of the filter 222 includeperforated polymer, textile, or sintered semi-permeable polymer. Theoutflow section 230 has an output orifice 232 that fluidically connectsthe outflow chamber 226 to the vacuum pump 80 for directly receiving thevacuum generated.

The container of the thrombus trap 200 is sealed when closed and in useduring a surgical procedure. In an exemplary embodiment, the thrombustrap 200 can be taken apart and opened for removal of the thrombus outof the trap chamber 224 and inspection by the surgeon or pathologist, aswell as for sterilization when the thrombus trap 200 is reusable.

It is noted that when a thrombus 4 is captured in the trap chamber 224,whether or not vacuum is still being applied, the trap chamber 224 isalso filled with blood. Thus, the thrombus 4 cannot be visualized evenif the entirety of the thrombus trap 200 is transparent for viewinginside by a user. To assist with visualization of the thrombus 4contained within the trap chamber 224, the thrombus trap 200 isconfigured to temporarily purge itself of fluids that visually impedeinspection of captured thrombus material. In an exemplary embodiment,therefore, the inflow section 212 is formed with an intake bleed valve214 fluidically connected to the vacuum channel 3 and to the trapchamber 224. The bleed valve 214 is configured to operate in a closedmode, in which any flow of air and/or fluid through the bleed valve 214and into the trap chamber 224 (or vacuum channel 3) is fully restricted,and a bleed mode, in which the bleed valve 214 intakes a fluid, inparticular, ambient air. (Alternatively, if desired, in the bleed mode,the bleed valve 214 can intake a clear liquid such as saline.) Duringthe closed mode operation, the exit of the bleed valve 214 is closed andaspirated materials are unhindered to flow through the thrombus trap 200from the input orifice 212 and out the output orifice 232 away towardsthe vacuum source, leaving aspirated thrombus and other solid matter inthe trap chamber 224. Accordingly, when the surgeon has captured athrombus 4 in the trap chamber 224 during a thrombectomy procedure, thesurgeon can immediately visualize that thrombus 4 by setting the bleedvalve 214 into the bleed mode, which, due to a relatively larger size ofthe bleed valve's 214 input opening and to a decreased resistance to thevacuum by opening to ambient air, causes the vacuum pump to draw ambientair rapidly into the trap chamber 224 and thereby evacuate all fluidfrom the trap chamber 224. During inspection, the bleed valve 214 can beconfigured to occlude the fluidic connection between the trap chamber224 and the vacuum channel 3. Actuation of the bleed valve 214 can beseparate from the controller 10 or mechanically connected to thecontroller 10 so that, when the controller 10 is in an unactuated statewhere aspiration is occurring, a bleed switch on the controller canactivate the bleed valve 214. The rapid inflow of air into the trapchamber 224 is directed by the descending pressure gradient between theoutside environment and the relatively low pressure existing within thevolume existing between the trap chamber 224 and the vacuum pump 80. Assuch, while the bleed 214 valve is open, airflow displaces fluids fromthe volume of the thrombus trap 200, leaving the volume mostly full oftransparent air, instead of opaque blood. This temporary transparencyallows for easier inspection of the material caught by the filter 222.The surgeon then can view the thrombus 4 unobstructed within the trapchamber 224. During this examination, the control of the bleed valve 214(which can be a mechanical or a processor-based controller) can causethe vacuum pump 80 to reduce vacuum or to shut off completely, at leastuntil the surgeon is ready to continue the thrombectomy procedure ifcontinuation is desired. When the bleed valve 214 is set back to theclosed mode and re-connection of the trap chamber 224 to the vacuumchannel 3 occurs, normal aspiration resumes. Alternatively the bleedvalve can be connected to a fluid flush line such as a saline drip bag.

Inspection of the thrombus 4 may be enhanced by providing the thrombustrap 200 with optical filters optimized for visual contrast, transparenttrap enclosures as described, built-in magnification or visualizationsystems, lighting, and/or sensor-based thrombus-detection methods.

In the exemplary configuration, the vacuum booster 100 is disposedupstream of the thrombus trap 200 and is on a side of controller 10opposite the thrombus trap 200 as shown in FIG. 21. Accordingly, tomaintain efficacy of the thrombus trap 200 as a terminus for allaspirated thrombi 4, vacuum booster configurations that might entrap orsignificantly damage or macerate the thrombus are less desirable. Oneexemplary embodiment of a gentler vacuum booster 200, instead of thepiston design of FIGS. 16 and 17, couples a section of the tubing of thevacuum tube 2 having a deformable interior volume with a mechanicalactuation mechanism. This mechanism is able to collapse and expand theinterior cross-section of a length of the vacuum channel 3 to provide anincrease or a decrease in pressure along that length. Another mechanicalembodiment for the vacuum booster having no pneumatic actuation takesenergy for vacuum boost from energy imparted by actuation of thecontroller 10 or from a separate energy input. For example, as userdepresses a lever in the controller 10 that occludes flow andtemporarily causes the column shift, the lever's motion also cocks andreleases a spring-loaded piston that creates the vacuum boost. Anotherexemplary embodiment of the vacuum booster places a screen between thevacuum chamber 114 of the vacuum booster 100 and the vacuum channel 3 ofthe aspiration system. This screen allows fluid communication betweenthe two interior volumes but occludes particulate matter from enteringthe piston bore defined by the vacuum chamber 114. A further exemplaryembodiment that guards against clogging/accidental maceration of thethrombus alters the piston configuration of FIGS. 16 and 17 by havingthe connection 140 be a flexible diaphragm mechanically disposed betweenthe surface of the vacuum piston 122 and the opening into the vacuumchannel 3. The diaphragm can be contained in and cross the actualopening of the vacuum channel 3, for example. Such a membrane transmitsvolumetric displacement while excluding all flow. The membrane can beseparate from the vacuum piston 122, fluidically coupled thereto, orattached. In each of these configurations, the volume through which thefluid column flows is unhindered to prevent entrapping or damaging thethrombus 4 when traveling thereby, whether the vacuum booster 100 is inan energized state or a resting state.

Both the vacuum booster and the blood-purging clot trap rely on thetimely and controlled application of either vacuum or ambient pressuresto specific parts of the device, namely the bleed valve 214 of thethrombus trap 200 or the plunger 120 of the vacuum booster 100. Theself-unclogging thrombectomy aspiration catheter described and shownherein can be provided with additional features actuated by the sameuser input as the self-unclogging function, e.g., at or by thecontroller 10, but which serve to either open or occlude additionalconduits for vacuum or atmospheric pressure air that control devicefeatures such as the self-purging thrombus trap 200 and/or the vacuumbooster 100.

The vacuum channel 3 of the vacuum tube 2 (and any other tubing withinthe catheter) can be coated with a hydrophobic coating, such as carnaubawax, for example, to decrease head loss during aspiration.

With an appropriate pressure sensor (for example, a piezoelectricdiaphragm transducer, an electromagnetic diaphragm transducer, astrain-gage diaphragm transducer, or a MEMS pressure integrated circuittransducer), the controller 10 can determine when the vacuum channel 3is clogged by a thrombus and automatically perform the uncloggingprocedures described herein. In an exemplary embodiment, a computerconnected to the sensor can detect a pressure drop and lack of flowassociated with a thrombus clog in or at the vacuum channel 3. When theclog is detected, the sensor triggers the sequence that haltsapplication of vacuum in the vacuum channel 3 and carries out the columnshift sequence. With respect to visualization of the thrombus 4 in thedevice, another exemplary embodiment of a sensor includes an opticalsensor that detects the presence of the thrombus in either or both ofthe distal opening of the vacuum channel 3 and the thrombus trap 200. Inthe latter configuration, the optical sensor associated with the trapsection 220 detects when the thrombus 4 is present and cause purging offluid by opening the bleed valve 214.

As set forth herein, the vacuum tube 2 can be made from variousmaterials. Some materials for the vacuum tube 2 have a relatively lowercompression strength, such as latex, silicone, and other syntheticrubbers. Other materials for the vacuum tube 2 have a relatively highercompression strength, such as Pebax®, polyurethane, and polyvinylchloride. Because the vacuum tube 2 within the controller 10 is subjectto expansion when positively pressured in the vacuum channel 3 and issubject to contraction when negative pressured, this flexible attributeof the material from which the vacuum tube 2 is made could possiblycontribute to a less effective column shift. In order to reduce theseeffects of pressure (both positive and negative) on the vacuum tube 2,the vacuum tube 2 can be reinforced with a braid or coil or othermechanical structure to support the portion of the vacuum tube 2 withinthe controller 10 against pressure changes. Where the vacuum tube 2 ismade from a material with a relatively lower compression strength, thesection of the vacuum tube 2 that resides within the controller 10 ismade as short as possible to minimize the expansion/contraction effects.

An alternative embodiment to the controller 10 of FIG. 1, whichindirectly operates on the vacuum channel 3 through the compressionroller 60, is shown in FIG. 22. In the exemplary embodiment of FIG. 22,the extrusion compressor is replaced with a volume changing controller300 that is directly fluidically connected to the vacuum channel 3 ofthe vacuum tube 3. The volume changing controller 300 has a barrel body310 with an interior 311 defining an input orifice 312 fluidicallyconnected to the vacuum channel 3. The barrel body 310 also defines aplunger orifice 314, a pump orifice 316, and a purge orifice 318. Aplunger 320 sealably connects to the interior 311 of the barrel body 310movably towards and away from the input orifice 314. When in theposition shown in FIG. 22, vacuum applied by the vacuum pump 80 isconnected to the distal opening of the vacuum channel 3 for aspirationof material. When a thrombus becomes clogged at the distal opening, thesurgeon presses the plunger 320 inwards. In a first portion of theinwards motion, a surface of the plunger 320 seals off the pump orifice316 to stop the application of vacuum to the vacuum channel 3. In asecond portion of the inwards motion, the plunger 320 moves all fluidcontained within the interior 311 and the vacuum channel 3 distally tocause the column shift. Reversal of the plunger reverses the columnshift and reapplies vacuum to the vacuum channel 3.

The plunger 320 can also be used to control purging of the thrombus trap200. The plunger is provided with a purge conduit 322. When the plunger320 is placed in a purge position, the plunger 320 closes off the vacuumchannel 3 from the vacuum pump 80 and fluidically connects the pumporifice 316 to the purge orifice 318 through the purge conduit 322. Inthis position, a fluid connected to the purge orifice, e.g., ambientair, is drawn through the purge conduit 322, through the purge orifice318, and into the thrombus trap 200.

Operation of the volume changing controller 300 is explained with regardto the system cycle diagram of FIG. 24.

-   -   State 1: Normal aspiration is occurring. The vacuum channel 3 is        not occluded. The volume changing controller 300 is in a rest        state where the vacuum pump 80 is connected to the vacuum        channel 3.    -   Transition A—Occlusion: Thrombus 4 occludes distal end of vacuum        channel 3. Controller 300 actuates (plunges) to occlude vacuum        channel 3 and stop vacuum flow distal of the controller 300.    -   State 2: Flow through the vacuum channel 3 has stopped.    -   Transition B—Unclogging: Controller 300 continues to plunge to        cause reverse flow in vacuum channel 3 for a metered volumetric        column shift.    -   State 3: Flow reversal stops.    -   Transition C—Return Column Shift: Controller 300 is reversed to        return column and accelerate thrombus 4 into catheter tip by        reconnecting the vacuum pump 80 to the vacuum channel 3.    -   Return to State 1 and Repeat: Normal aspiration occurs.

FIGS. 25 to 41 illustrate an exemplary embodiment of an aspirationthrombectomy system 400 operating with an automatic, rapid, and repeatedonset of pressure change. An aspiration catheter 410 is diagrammaticallyindicated in FIG. 26 leading from distal orifices of a pair of valves420, 440, which in this exemplary embodiment are pinch valves 420, 440.One of these valves is a pinch valve 420 to control vacuum flow and isconnected between the aspiration catheter 410 and the aspiration pump(e.g., vacuum pump 80). The other of these valves is a pinch valve 440to control vent flow and is connected to a supply of vent liquid. In anexemplary embodiment, the vent liquid can be any of albumin, d5 W water,normal saline, half-normal saline, and lactated Ringer's solution, toname a few. The vent liquid can also be any other biocompatible fluidsuch as contrast media or tissue plasminogen activator (tPa). With suchfluids, the catheter 410 can perform different functions. For example,switching the vent liquid to contrast media after it is believed that aclot has been successfully removed allows the surgeon to inject thatmedia into the vessel to confirm removal of the clot. This issignificant because the catheter 410 changes from the aspirationfunction to the contrast injection function without any significantmovement within the vasculature. With standard aspiration catheterswhere a clot becomes lodged in the distal end, the entire catheter needsto be removed from the patient and, if contrast needs to be injected atthe site, the catheter needs to be reintroduced through the vasculaturejust to perform this visualization. The vent liquid can be atatmospheric pressure or at a higher or lower than atmospheric pressure.

In an exemplary configuration, these valves 420, 440 are mounted to abase 401. Operatively associated with the pinch valves 420, 440 arerespective cams, a vacuum cam 430 and a vent cam 450. These cams 430,450 are connected to a cam shaft 460. A first shaft end 462 of the camshaft 460 is fixedly connected to a shaft bearing 470 in a freelyrotatable manner. The shaft bearing 470 has a bearing body 472 mountedto the base 401. A second shaft end 464 of the cam shaft 460 isconnected to a shaft drive assembly 500. The shaft drive assembly 500comprises a motor 510, a transmission or gear box 520, a shaft coupler530, and a motor controller assembly 550.

The transmission 520 has an output shaft 522. To connect thetransmission 520 to the cam shaft 460, a first coupler end 532 of theshaft coupler 530 is connected to the output shaft 522 and a secondcoupler end 534 of the shaft coupler 530 is connected to the secondshaft end 464. In this manner, rotation of the motor 510 corresponds toa rotation (at the same or different speed based upon the gearing of thetransmission 520) of the cam shaft 460 with a corresponding rotation ofthe vacuum and vent cams 430, 450.

Control of the motor 510 originates from the motor controller assembly550, which comprises a controller 560, a positional encoder 570 and apositional reset assembly 580. In an exemplary embodiment, thecontroller 560 is a microcontroller that has a user interface (UI)comprising user inputs that include, for example, control buttons tooperate the aspiration thrombectomy system 400 in various states,examples of which are described in further detail below. The controller560 with the UI is illustrated diagrammatically in FIG. 30. To isolateparts from fluid, in the exemplary embodiment, the motor 510, thetransmission 520, the shaft coupler 530, and the motor controllerassembly 550, 560, 570, 580 are contained in a motor assembly housing552. The connection of the motor assembly housing 552 to the cam shaft460 is sealed fluidically with a shaft seal 554. Similarly, the cams430, 450, the cam shaft 460, and the shaft bearing 470 are covered witha cam housing 466. The controller 560 is indicated in FIG. 30 asseparate from the motor assembly housing 552 (either wired or wireless)but it can also be integrated into or attached to the motor assemblyhousing 552. In a wireless configuration, the controller 560 can be anapp on a computer or smartphone, for example, with all of the UI beingavailable through a touchscreen.

The vacuum and vent cams 430, 450 are fixed rotationally to the camshaft 460. These cams 430, 450 have various cam profiles to operate thevalves 420, 440. It is desirable to know the exact rotational positionof the cams 430, 450 and, therefore, cam shaft 460, so that thecontroller 560 can set the valves 420, 440 in whatever state that isdesired. Because the motor 510 rotates freely and can end its rotationat any rotational position, it is desirable to know the exact rotationalposition of the cam shaft 560 at all given times. Accordingly, the motorcontroller assembly 550 includes the positional encoder 570 associatedwith the motor 510. With this association, the controller is providedwith information on the exact rotational state of the cam shaft 460 and,therefore, the cams 430, 450. The positional encoder 570 comprises anencoder disk 572 and an encoder circuit 574. The encoder 570 is able todetect and report out to the controller 560 the current relativerotational position of the motor 510 at any point in time.

Those of skill in the art know that the motor 510 and/or the positionalencoder 570 can drift in use. To account for and correct any drift, themotor controller assembly 550 comprises the positional reset assembly580. This positional reset assembly 580 assigns a single rotationalposition of the cam shaft 460 as a reset point and every time thatposition crosses a zero-line the positional encoder resets the positionof the motor 510 to zero, which in turn allows the system to know theabsolute position of the cam shaft 460. In an exemplary embodiment, thepositional reset assembly 580 comprises a photodiode 582 and a flag orinterrupter 584. As shown in FIG. 30, the flag 584 is fixed to the shaftcoupler 530. The photodiode 582 is placed at the path of the flag 584 sothat the flag 584 interrupts the photodiode 582 once for each rotationof the cam shaft 460. This exemplary embodiment allows for immediatecorrection of any skipped steps of the encoder 570.

The exemplary embodiment of the pinch valves 420, 440 is explained withregard to FIGS. 31 to 33 using the vent pinch valve 440. Each valve 420,440 comprises a valve body 422, 442 defining a vacuum or vent lumen 424,444. An elastomeric tube 426, 446 is secured within the lumen 424, 444at each end of the tube 426, 446. Exemplary embodiments for thisconnection include but are not limited to fusing, compression sealing,and fixation with an adhesive. Accordingly, the tube 426, 446 spans anextent of the lumen 424, 444 with an intermediate portion of the tube426, 446 unattached to the lumen 424, 444. A lumen of the tube 426, 446fluidically connects a distal end of the lumen 424, 444 (to the left ofFIGS. 31 and 32) to the proximal end of the lumen 424, 444 (to the rightof FIGS. 31 and 32). The intermediate section of the valve body 422, 442defines a follower connection in which is movably secured a cam follower421. A first end of the cam follower 421 is biased against the outersurface of the cam 430, 450 with a non-illustrated bias device or issimply trapped in place. The opposing second end of the cam follower 421rests against the intermediate portion of the tube 426, 446.Accordingly, when moved by the cam 430, 450 towards the tube 426, 446,as shown in FIG. 32, the cam follower 421 fluidically seals off thelumen of the tube 426, 446 and, when allowed to return away from thetube 426, 446, as shown in FIG. 31, the cam follower 421 opens the lumenof the tube 426, 446. In the exemplary embodiment, the cam follower 421is pill-shaped but it can be formed in any shape to provide the functionof closing off the tube 426, 446.

Both a vacuum line 402 and a vent line 404 are connected through theselectively openable valves 420, 440 to a proximal end of the aspirationcatheter 410. In operation, the vacuum cam 430 and the vent cam 450 pushdown on the respective cam followers 421, which pinch down the shortsections of tubing 426, 446, each respectively fluidically connected tothe vacuum line 402 and the vent line 404. When the vacuum line 402 isopen and the vent line 404 is closed, vacuum is drawn on the aspirationcatheter 410. When the distal end of the catheter 410 is clogged with aclot, the closure raises a vacuum level within the catheter 410 to full(the greatest current vacuum generated by the vacuum pump). This closurecreates a delta in pressure between the internal lumen of the catheter410 and the environment external to the catheter 410, which changesqueezes down the body of the catheter 410 both radially andlongitudinally (e.g., the diameter and length become incrementallysmaller). This change also draws out a small volume of liquid fromwithin the lumen of the catheter 410. In an exemplary embodiment, thevolume is approximately 0.2 ml. The end effect is the creation of aspring-like force within the catheter 410 that wants to expand thecatheter 410 back to its steady state, but when the vacuum line 402 isclosed off, that cannot happen. Thus, the vacuum is stored as potentialenergy until the vent line 404 is opened (as can be seen in FIG. 26, forexample, the vacuum and vent lines 402, 404 are connected togetherdistal of the valves 420, 440). When the vent line 404 is opened, thereis an in-rush of fluid because of the pressure delta. This rush of fluidbalances the radial force of the catheter 410 and draws in fluid tocreate a distally directed momentum in the column of fluid residing inthe catheter 410 distal of the valves 420, 440. The momentum causes asmall amount of fluid to move through a distal portion of the catheter410 and create a small distal movement of the clot that is stuck in thedistal opening at the end of the catheter 410. Once the clot is nolonger stuck at the distal opening, it is able to be moved proximallyinto and through the catheter 410 with subsequent vacuum imparted to thecatheter 410. Repeated selective actuation of vacuum and ventingmacerates the clot at the distal opening, thereby reforming it into astate where it can be completely drawn into the lumen of the catheter410 and out of the vasculature. The flow of fluid forward in thisexemplary embodiment is intentional, which is in contrast to otherexemplary embodiments herein where substantially no forward flow occurs.

The system 400 can be operated in various modes to remove clots in thevasculature. Rotation of the cams are measured in degrees, a fullrotation being 360° of movement. In a first exemplary embodiment, thevacuum cam 430 is configured to establish vacuum in the catheter 410through approximately 220° of rotation. The vent cam 450 is configuredto have venting on through approximately 80° of rotation. Theconfiguration of the cams 430, 450 stop both venting and vacuum betweeneach respective application of vacuum and venting, for example, with a30° rotation. This configuration, therefore results in operation statesaccording to Table 1 below.

TABLE 1 State Vacuum Venting Cam Angle Off 0 0  0 to +30 Vac 1 0  +30 to+250 Off 0 0 +250 to +280 Vent 0 1 +280 to 0   As soon as the vent is opened, there is an in-rush of fluid to balanceout the vacuum pressure, then the vent line 404 is closed and the vacuumline 402 is opened, suddenly causing a rapid decrease in pressure thatserves to forcefully pull the clot to the catheter. It is desirable,therefore, to close both vacuum and vent lines before resuming vacuum.

In another exemplary embodiment, the vacuum cam 430 is configured toestablish vacuum in the catheter 410 through approximately 220° ofrotation. The vent cam 450 is configured to have venting on throughapproximately 80° of rotation. Thus, there is created, in a desirablesecond exemplary configuration, a pause between vacuum draw in thecatheter and venting of the catheter and another pause between ventingof the catheter and resuming vacuum draw in the catheter. In thisexemplary configuration, the pause can be through approx. 30° ofrotation. To create a purge state, where vacuum and venting occursimultaneously, the vent cam 450 has a small inwards depression in aposition of the vent cam 450 that occurs during a long vacuum-on stage(e.g., between +30° to +250°). The extent of the venting is configuredto not provide a significant change in pressure or change in the vacuumenergy but, instead, is configured to create a single rotation positionof the cams 430, 450 where the motor control assembly 550 can stoprotation of the cam shaft 460 in that orientation where both the vacuumline 402 and the vent line 404 are connected to the catheter 410, whichallows the user to purge out any air that might be present in the system(e.g., in the vacuum line 402, the vent line 404, and/or the catheter410). The extent of the depression can be such that it only partiallyopens the vent to reduce the amount of vent liquid that is drawn induring this purge state. This purging can be a known position of the camrotation and is placed in that position to ensure that all lines in thesystem 400 are cleared of air. Such a configuration results in operationstates according to Table 2 below.

TABLE 2 State Vacuum Venting Cam Angle Off 0 0  0 to +30 Vac 1 0  +30 to+120 Purge 1 1 +120 to +140 Vac 1 0 +140 to +250 Off 0 0 +250 to +280Vent 0 1 +280 to 0   

A third alternative configuration for operation of the system 400 caninclude a full-time vacuum with a pulsed venting including the operatingstates according to Table 3 below.

TABLE 3 State Vacuum Venting Cam Angle Vac 1 0    0 to +120 Purge 1 1+120 to +150 Vac 1 0 +150 to 0   An opposite configuration to the states of Table 3 can including afull-time venting with a vacuum overlap.

A fourth alternative configuration for operation of the system 400 caninclude a vacuum during venting, which configuration includes theoperating states according to Table 4 below.

TABLE 4 State Vacuum Venting Cam Angle Purge 1 1  0 to +30 Vac 1 0  +30to +250 Off 0 0 +250 to +280 Vent 0 1 +280 to 0   An opposite configuration to the states of Table 3 can include afull-time venting with a vacuum overlap.

A fifth alternative configuration for operation of the system 400 caninclude a venting during vacuum, which configuration includes theoperating states according to Table 5 below.

TABLE 5 State Vacuum Venting Cam Angle Off 0 0  0 to +30 Vac 1 0  +30 to+250 Purge 1 1 +250 to +280 Vent 0 1 +280 to 0   

In further alternative configurations, there can be a variationoverlapping of venting and vacuum, which would delete one or more of theOFF states in any of the state tables above.

The cam-driven valves 420, 440 allow the positional encoder driven motorto create positions for vacuum, venting, off, and purge. The motorcontroller assembly 550 allows the cams 420, 440 to be controlled by anyfrequency, e.g., they can be set to move through the various states atany given speed, for example, at 4 Hz. The frequency at which the motorruns may be more appropriate to run at lower frequencies such as 0.5 Hz,1 Hz, or 2 Hz. Alternatively, it may be more effective to run at higherfrequencies such as 8 Hz, 12 Hz, or 16 Hz. The motor control assembly550 can also dynamically change the rate of cam shaft 460 rotation tosweep the frequency of rotation. In exemplary embodiments, the step inspeed is in a range from 1 Hz to approximately 4 Hz, the change inincrement is between approximately 0.25 seconds to approximately 5seconds, and the range of rotation is between approximately 2 Hz toapproximately 12 Hz. One example for the step, increment, and range is 2Hz and 1 second increments in the following progression 2Hz/4/6/8/10/12/10/8/6/4/2/ . . . . Another example is 4 Hz with 0.5 secincrements in the following progression 4 Hz/8/12/8/4/ . . . . Inexemplary embodiments, the system uses the higher frequencies in the 8Hz to 12 Hz range, which has been observed to have less movement of theproximal end of a clot stuck at the distal end of the catheter 410.Alternatively, further increments can be used to sweep the frequencythrough complex forms, such as sine, sawtooth, stepped, and pulsingvariations.

In an exemplary alternative to the pinch valves 420, 440, the valves canbe solenoid-driven pinch valves or voice coil actuators. In anotherexemplary alternative, a rotational pintle valve can be used, as shownin FIGS. 42 to 46. The first valve state shown in FIGS. 42 to 44 can,for example, be a vacuum-on/vent-off state and the second valve stateshown in FIGS. 45 and 46 can be a vacuum-off/vent-on state.

It has been determined that the most rapid onset of vacuum and ventingis desirable. To create this rapid onset, the cams 430, 450 start vacuumand venting, respectively, with a cliff 452 in the shape of the cam 430,450. Sudden creation of vacuum creates a rapid decrease of pressureinside the catheter 410, which draws the clot aggressively against thedistal end of the catheter 410. Venting, as described above, creates adistal momentum that unsticks the clot and repetition of the vacuum andventing causes mechanical maceration of the clot at the distal openinguntil the clot completely enters the lumen of the catheter 410 and isremoved from the vasculature. Therefore, the instant system 400 can bedescribed as a Rapid Onset Aspiration Repeater or ROAR.

The control carried out by the motor controller assembly 550 has aselection of user-actuated buttons. In an exemplary embodiment, onebutton causes both vacuum and venting to be shut off, i.e., offoperation. One button causes vacuum to occur in a continuous manner,i.e., manual control. One button causes venting to occur in a continuousmanner, i.e., manual control. One button causes the cam shaft 460 torotate the cams 430, 450 to the position in which the vacuum and ventlines 402, 404 can be purged, i.e., the purge function. One buttoncauses the system to run or pulse repeatedly according to a desired setof states (e.g., according to any of Tables 1 to 5) along with aselection of any number of sets for step, increment, and range. As such,if the surgeon desires to use the system 400 as a simple thrombectomydevice, the surgeon can just use the vacuum button. In this condition,the encoder 570 assists to have the cam shaft 460 to rotate to aposition in which vacuum is open. The vacuum pump runs with a fully openvacuum until the surgeon releases the button. If the surgeon wants topurge or inject contrast, for example, then the surgeon can use the ventbutton to have the encoder 570 assist to rotate the cam shaft 460 to aposition in which the vent is open. Likewise, the off button rotates thecam shaft 460 to a position where the cams 430, 450 close both thevacuum and vent lines 402, 404. The purge button causes rotation of thecam shaft 460 to a position where the cams 430, 450 allow simultaneousvacuum and venting.

In an exemplary embodiment of the run or ROAR mode, rotation of the camshaft 460 is between approximately 0.5 Hz and approximately 25 Hz,further, approximately 6 Hz and approximately 16 Hz, in particular,between approximately 8 Hz and approximately 12 Hz. In this exemplaryROAR cycle, the cam shaft 460 is rotated for between approximately 10seconds and approximately 30 seconds and, during that time, the motorcontroller assembly 550 causes the motor 410 to sweep throughfrequencies between approximately 2 Hz and approximately 12 Hz.

As set forth above, the elastomeric tube 426, 446 is attached to distaland proximal locations of the valve lumen 424, 444. Compliance in thesystem 400 distal of the vacuum valve (described above as includingreduction of the diameter and/or length of the catheter 410 as well ascompliance of the tube 426, 446) when vacuum is applied to the catheter410 and a clot is stuck at the distal end determines how much fluid isdrawn out when the system 400 is under full vacuum and, conversely, howmuch fluid rushes back into the system 400 when that state is released.In other words, with a greater amount of compliance distal of the valves420, 440, momentum imparted to the stuck clot by the column of fluidincreases. It is desirable to have a minimal amount of momentum transferfrom the fluid column to the stuck clot to unstick the clot sufficientlyso that the next vacuum cycle macerates the clot against the distal endof the catheter 410 and causes it to enter the lumen of the catheter 410and be removed from the vessel. To minimize this compliance (which isfixed for a given catheter 410), this tube 426, 446 is made as short aspossible to still allow valve operation by the cam follower. Complianceas used herein refers to mechanical compliance of the catheter 410 andthe tube 426, 446; it does not refer to any air that might be in thesystem 400, which air is purged before use as set forth herein. Thisdesire for a reduction in compliance is one reason the valving system isconnected directly to the proximal end of the catheter 410. This closeconnection minimizes overall compliance. In an exemplary embodiment, thevalving system can be located away from the catheter 410 and, in such acase, substantially non-compliant tubing is desired. This configurationmay experience lower performance due to the excess compliance.

To determine the status of a clot at the distal end of the catheter 410,the system 400 is put in the ROAR mode. If there are no sensorsassociated with the system 400, a surgeon cannot distinguish thesituation when a clot is corked during ROAR or not. The surgeon has toturn off ROAR and visualize whether the catheter is corked (in whichnothing is being drawn in by the catheter 410) or is not corked (inwhich blood is being drawn into the catheter 410). With the differentsituations of aborting pulse based on flow and pulsing until not corked,it is hard to know when a clot is corked.

The vent line 404 is connected to a vent liquid reservoir (notillustrated), which can contain for example, any of albumin, d5 water,normal saline, half-normal saline, and lactated ringers. When a fluid isused to vent the system 400, as described above, all air can be purgedout of the system 400. Additionally, knowing that a given amount of ventliquid is used at various stages of clot removal can allow the user tocorrelate removal of a clot into the catheter after being stuck at thedistal end to a rate of vent liquid use. In other words, the amount ofvent liquid is different when the clot corked from when it is notcorked. Thus, a user or a sensor can look at or measure vent liquid useto determine to turn off the system. If the catheter 410 is aspiratingwithout obstruction (uncorked), then a significant flow of blood willexit the system 400. If the catheter 410 is aspirating while corked,then no blood will appear at the vacuum exit. During a ROAR operationand the catheter 410 is uncorked, the user/sensor will detect some bloodat the vacuum exit. Finally, during the ROAR operation when the catheter410 is corked, the vacuum exit will receive some fluid that is acombination of both blood and vent liquid and, in this state, the flowrate of the vent liquid can indicate if the catheter is corked oruncorked.

If a surgeon visualizes free flow during vacuum and see a captured clot(for example, in the thrombus trap 200), then the surgeon has theability to perform a contrast injection with the catheter 410 to confirmrevascularization without moving or removing the aspiration catheter410. This is in contrast to current state-of-the-art aspirationcatheters where the catheter removes the clot by holding the clot corkedon the end and the surgeon retracts the entire catheter to drag out thecorked clot. The increased ability of a smaller diameter catheter to beable to fully ingest or secure a better grip on the clot by drawing agreater amount of it into the catheter is a significant benefit. Manyclots are deep enough into the anatomy that it is difficult to get largecatheters to the site of the clot. If a smaller diameter catheter canhave increased effectiveness through ROAR than a greater number of clotscan be accessed and retrieved.

It is noted that one desirable goal to achieve with the system 400 is tofully ingest a clot and bring it back a standard aspiration canister (ina typical thrombectomy end reservoir) or into the thrombus trap 200.When using a standard aspiration canister and the thrombus trap 200, thesystem 400 can use the vent liquid to flush the thrombus trap 200through the intake bleed valve 214 instead of using air. This allowsretention of vacuum pressure in the aspiration canister.

Turning now to embodiments that create maceration but without theforward flow, FIG. 47 illustrates diagrammatically an exemplaryembodiment of an aspiration thrombectomy system 600 that operates in aROAR mode. The system 600 comprises a vacuum source 610 fluidicallyconnected to an input of a controllable vacuum valve 620. (Parts of thevacuum source 610, such as the collection canister, are not illustratedin FIG. 47 for reasons of clarity but are detailed below.) The vacuumvalve 620 is fluidically connected to a vacuum input 632 of a manifold630. The connection can be direct or through a conduit, such as siliconetubing. A vent fluid source or reservoir 640 containing a vent liquid642 is fluidically connected to a controllable vent valve 650. The ventliquid 642 can be, for example, any of albumin, d5 water, normal saline,half-normal saline, and lactated ringers, to name a few. As used herein,“controllable” means that the device is able to be selected betweenvarious states, the selection including analog and/or digital switching.One exemplary embodiment is a digital switching between an open positionand a closed with a single command (e.g., a change of bit 1/0). Theentire working channel of the aspiration thrombectomy system 600 is tobe free from air or other gaseous bubbles during use.

The vent fluid source 640 has a sufficient amount of vent liquid in thereservoir that will not end during a given surgical procedure and thisprevents any possibility of air entering the system. If the vent fluidsource 640 is flexible, such as with fluid supplied by a parenteralfluid containment bag or an intravenous therapy bag, the gas-freecontainer will shrink as the vent liquid 642 is used. If the vent fluidsource 640 is inflexible and has an air or gas pocket, as in areplaceable/removable and sterilizable container, the conduit thattransfers the vent liquid 642 from the vent fluid source 640 to the ventvalve 650 is at a level within the reservoir to keep the input of thatconduit submerged within the vent liquid 642 throughout a givenprocedure.

A ROAR catheter 660 defines a working lumen 662 fluidically connecting adistal end 664 thereof to a proximal manifold connector assembly 670 ata proximal end of the ROAR catheter 660, which assembly 670 is describedin greater detail below. The ROAR catheter 660 is configured to operatein relatively small vessels. Thus, in an exemplary embodiment, the lumenhas an internal diameter of between approximately 0.038″ andapproximately 0.106″ and, in particular, an internal diameter of betweenapproximately 0.068″ and approximately 0.088″. The proximal manifoldconnector assembly 670 fluidically connects the lumen 662 to theinterior of the manifold 630 and, thereby, the manifold 630 fluidicallyconnects the lumen 662 to the vacuum source 610 through the vacuum valve620 and to the vent fluid source 640 through the vent valve 650. In usewithin a vessel, the lumen 662 is filled with a liquid column having aproximal portion and a distal portion. Depending on the context usedwith respect to the catheter 660, the proximal and distal portions ofthe liquid column can be a given amount (e.g., less than 20 microlitersor less than 5 microliters), can be a given length (e.g., a few mm orcm) or it can be an instance of the column that is approximated by usingstatistical flow analyses. For example, when discussing whether a distalportion of the fluid column exits the distal end of the lumen 662, thatdistal portion is a measurable distance at the distal end of the liquidcolumn equal to an instance of liquid present at the plane of the lumendistal exit. In the realm of statistical analysis in this example, thedistal portion is a last distal finite element in a finite elementanalysis (FEA) of the liquid column. Here, the system 600 is used tosubstantially prevent forward flow. The term “forward flow” is usedherein to define an amount of liquid in the lumen 662 that exits thedistal end 664 in a distal direction. Forward flow is defined as greaterthan 6 microliters of fluid (approximately 1 mm of catheter length of ID0.071″=5.7 [IL). Less forward flow is also included in this definition.For example, the amount of forward flow can be restricted to no greaterthan 2 microliters or, in a particularly beneficial embodiment, forwardflow is approximately zero microliters. In each case, no forward flowmeans that substantially no liquid exits the distal end 664 in thedistal direction.

Operation of the aspiration thrombectomy system 600 occurs through acontroller 700, which can be an analog controller or a digitalcontroller. Examples of the analog controller are shown in FIGS. 25 to46. An example of a digital controller is described in further detailbelow. One exemplary configuration for a digital controller is amicrocontroller manufactured by Microchip Technology, Inc. Thecontroller 700 is operatively connected to each of the vacuum valve 620and the vent valve 650 (and to a vacuum motor as described below). Thecontroller 700 selectively opens and closes the vacuum and vent valves620, 650 such that, when the vacuum valve 620 is opened, the vacuumsource 610 is fluidically connected to the liquid column in the lumen662 and, when the vent valve 650 is opened, vent liquid 642 isfluidically connected to the liquid column in the lumen 662. The timingof these valves is significant so that the controller 700 can change alevel of vacuum at the distal end 664 and prevent the distal portion ofthe liquid column in the lumen 662 from exiting the distal end664—substantially no forward flow. There are two significant actionsthat contribute to forward flow when operating the valves 620, 650:compliance of the catheter system and the water hammer effect. Each willbe discussed in turn. Exemplary configurations of the vacuum and ventvalves is shown in FIGS. 25 to 36 in FIGS. 42 to 46. Configurations forthe valves include spool valves, pinch valves, rotary valves, and rotaryvalve having a pintel design.

To explain timing of the valves to eliminate forward flow, reference isfirst made to the system depicted in the diagram of FIG. 47. It is notedthat the ROAR catheter 660 is a flexible body and, therefore, it hascompliance both in the radial direction and in the longitudinaldirection. When the distal end 664 is corked with a thrombus (as shownin FIG. 47), vacuum is being applied to the lumen 662. Compliance of thecatheter 660, therefore, causes reduction in the diameter of thecatheter and reduction in the length of the catheter. When the catheter660 corked, no flow occurs in the lumen. By having pressure lower thanatmosphere within the lumen 662, the catheter 660 shrinks and reduces(shortens radially and longitudinally). This shrinkage acts like aspring squeezing down on the lumen in the catheter—in other words, it isa storage of potential energy. If the vacuum source is then cut off(e.g., the vacuum valve 620 is closed) and the vent valve 650 is openedto the vent fluid source 640, then the catheter 660 elongates and actsas a piston pulling against the vent liquid 642. Further, the ventliquid 642 is at a higher pressure (e.g., atmospheric pressure orslightly elevated by having a higher physical position than the patient)than the fluid in the lumen 662. Consequently, an amount of the ventliquid 642 enters through the vent valve 640 into the manifold 630 andthen into the lumen 662 through the proximal manifold connector assembly670. As the vent liquid 642 flows in and the catheter 660 expands to itsnormal or free steady state, momentum is created in the fluid columndirected towards the distal end 664, referred to herein as a pressurepulse or pressure wave. In other words, a “pressure pulse” or “pressurewave” is momentum within a column of fluid that can act to move a distalportion of the fluid column in the catheter lumen distally out from adistal end of the catheter. This term relates to a given cycle of thevacuum and vent valves 620, 650 and is not limited to a single pressuretransmission with that cycle. A pressure pulse, therefore, can includemultiple pressure differentials with a given cycle of the vacuum andvent valves 620, 650. Thus, by adjusting a timing of the vacuum and ventvalves to match a compliance and length of a particular catheter system(which can include the catheter and also the manifold and valves andother lumens in line with the catheter), a ROAR effect can be achievedfor that catheter. In particular, one way to achieve the ROAR effect andprevent forward flow of the distal portion out from the distal endduring each cycle is by regulating a timing of the vent valve 650.

Prior art aspiration thrombectomy systems periodically open and close avacuum valve. Fluid rushes into the distal end of the catheter while thevacuum valve is open and vacuum is being applied to the fluid column.When the vacuum valve is closed, liquid rushing proximally through thelumen stops by hitting the closed vacuum valve. This causes pressure tobuild at the vacuum valve and create a bounce-back wave that carriesmomentum distally towards the distal end and ejects an amount of fluiddistally from the distal end of the catheter. This action is referred toas a water hammer effect. The prior art repetitively opens and closesthat vacuum valve. Thus, an amount of liquid ejects in a periodic mannerout of the distal opening in those devices. This forward flow phenomenais undesirable in the area of thrombus removal because, when liquid isallowed to eject from the distal end and the physician is causing thedistal end to approach the thrombus, the liquid could or will move thethrombus further distally, or it could break the thrombus up to allowarterial pressure to push the broken pieces further downstream, e.g.,into smaller brain arterial vessels. It would be, therefore, desirableto entirely prevent any distally directed pressure pulse reaching thedistal end of the aspiration catheter in a thrombus aspiration removalsystem. As described herein, the system 600 has a response to the waterhammer effect that is tuned to achieve a maximum water hammer effectwithout causing forward flow, which response achieves the most effectiveengagement and disruption of the thrombus.

Proximal and distal pressure measurement devices 690, 692 areillustrated diagrammatically in FIG. 47. In this exemplary embodiment,the proximal pressure measurement device 690 is adjacent or within theproximal manifold connector assembly 670 and/or within the proximalportion of the fluid column, and the distal pressure measurement device692 is adjacent or within the distal end 664 or within the distalportion of the fluid column. An exemplary embodiment for measurementdevices 690, 692 include a pressure transducer manufactured byTransducersDirect.com.

Measurement in the fluid column of the catheter 660 at or adjacent themanifold 630 and adjacent the distal end 664 reveals a time delay intravel of the pressure pulse—the pressure rises at the manifold 630first and then pressure rises at the distal end 664 later. By knowingthe time delay and the distance between the sensors, the speed of thewave can be calculated. By knowing the distance from the most distalsensor to the tip of the catheter 660, the time it will take for thewave to travel to the distal tip can be calculated. This information canbe used by the controller to time the valves properly to stop thepressure pulse. If the pressure pulse is allowed to travel all the wayto the distal end 664, then a distal portion of the fluid column in thelumen 662 will exit the distal end 664, e.g., forward flow. If, duringthis time, the distal end 664 is corked with a thrombus 4, that pressurepulse could or will eject the thrombus 4 distally. Alternatively, if thedistal end 664 is approaching a thrombus 4, any pressure pulse exitingthe distal end 664 could or will move the thrombus 4 further distally.Movement of the thrombus 4 in a distal direction before or after it hasbeen captured and corked at the distal end 664 of the catheter 660 is tobe avoided. Therefore, the pressure pulse needs to be reversed orstopped before that pressure pulse reaches a point where it could movethe thrombus 4 either further downstream or off of the distal end 664 inthe distal direction. Such reversal is referred to herein as “quelling”the pressure pulse.

Operation of the aspiration thrombectomy system 600 with the ROAR effectdoes not produce the same results as prior art catheters. When operatedwith the distal end 664 unobstructed, the vacuum valve 620 and the ventvalve 650 are periodically opened and closed. Fluid rushes into thedistal end 664 of the catheter 660 and into the canister of the vacuumsource 610 while the vacuum valve 620 is open and vacuum is beingapplied to the fluid column. When the vacuum valve 620 is closed, thesudden stop of flow creates the pressure wave generated as describedabove due to the water hammer effect from the closing of the vacuumvalve 620. The controller 700 is timed to control the vacuum and ventvalves 620, 650 to create the ROAR effect even when the distal end 664is open to vasculature and, therefore, any distally directed pressurepulse in the aspiration thrombectomy system 600 is quelled so thatsubstantially no forward flow occurs during a thrombus retrievalprocedure. Through experimentation, net flow of liquid at the distal end664 remains positive in the proximal direction—in other words, whileoperating with the ROAR effect in the corked or un-corked state, liquideither moves through the distal end 664 towards the vacuum source (whenun-corked) or does not flow at all (when corked). In both circumstances,substantially no liquid exits the distal tip 610.

To accomplish the ROAR effect, the change in the level of vacuum at thedistal end is at least approximately 15 inHg, further, at leastapproximately 20 inHg, and, in particular, at least approximately 25inHg. A time for the change in the level of vacuum from low to high orfrom high to low at the distal end is no greater than approximately 50ms, further, no greater than approximately 30 ms, and, in particular, nogreater than approximately 20 ms. This change can be referred to as amaximum pressure delta. Various combinations of these variables includea change in the level of vacuum of approximately 15 inHg and a time forthat of no greater than 50 ms, or the change in the level of vacuum ofapproximately 20 inHg and a time for that change of no greater than 30ms, or the change in the level of vacuum of approximately 25 inHg and atime for that change of no greater than 20 ms.

The ROAR catheter 660 is operated to quell all pressure pulses in anexemplary embodiment according to the graph of FIG. 48. The state of thevacuum valve 620 is shown in the waveform at the top of the graph andthe state of the vent valve 650 is shown in the waveform at the bottomof the graph. The repetitive cycle starts at time 0 with the valvestarting to open in this exemplary embodiment. At time 1, the vacuumvalve 620 is fully open and the vent valve 650 is closed. Vacuumcontinues until time 2, when the vacuum valve 620 starts to close.Closing of the vacuum valve 620 is not instantaneous and, therefore, thevacuum valve waveform decreases at a sharp angle and is fully closed attime 3. After the vacuum valve 620 is closed, at time 4, the vent valve650 starts to open. This closing of the vacuum valve 620 initiates awater hammer and the closing of the vacuum valve 620 and subsequentopening of the vent valve 650 causes vent liquid 642 to enter themanifold 630 (and possibly the proximal end of the lumen 662). Thepotential energy stored in the compliant catheter 660 is also allowed torelease due to the change in pressure from the negative pressuregenerated by the vacuum source 610 to the relatively larger pressure(e.g., arterial) existing in the vent fluid source 640. This combinationof events initiates a pressure pulse at time 2 that travels distallythrough the lumen 662 towards the distal end. If there was no furtherchange in the valves 620, 650, then liquid in the column will eject outfrom the distal end 664, i.e., forward flow. However, as shown in FIG.48, after a relatively short vent-open time compared to the vacuum-ontime, the vent valve 650 is closed (at time 7) and, shortly thereafter,the vacuum valve 620 is opened. This means that, while the pressure waveis travelling distally along the length of the lumen 662 of the catheter660, when the vent valve 650 is closed to turn the vent liquid 642 offand the vacuum valve 620 is opened to turn vacuum back on (time 0 of therepeating waveform), switching of these valves 620, 650 causes ventliquid 642 to cease entering the manifold 630 and to move the fluid inthe manifold 630 and in the lumen 662 proximally into the collectioncanister 612 of the vacuum source 610 (see, e.g., FIG. 55). Thus, areverse momentum is imparted within the fluid column. This reversemomentum is sufficiently large enough to prevent the pressure pulse fromever reaching a point where the distal portion of fluid in the lumen 662exits the distal end 664—thereby quelling the pressure pulse andpreventing forward flow. The ROAR effect, therefore, retains a level ofpressure at the distal end at less than or equal to physiologicalpressure. The area 690 of the two waveforms shown in FIG. 48 includes atime at which the pressure pulse has been quelled. The waveforms repeatin a periodic manner to continue the distal-then-proximal momentum pulsewithout ever allowing the distal portion to exit the distal end 664 ofthe catheter 660. The rapid change in pressure at the catheter tip fromnear full vacuum to nearly zero vacuum pressure is the ROAR effect.Under the ROAR effect, pressure at the distal end 664 can rise to justshort of being arterial pressure and reversal of that rise is, then,started due to the reestablishment of vacuum. This allows the aspirationthrombectomy system 600 to approach a thrombus 4 without impartingdistal movement to the thrombus 4 and to retain the corked thrombus 4 atthe distal end 664 without any distal movement of the thrombus 4 causedby a change in pressure within the fluid column.

Another exemplary embodiment for creating the ROAR effect with thecatheter 660 utilizing the vacuum valve 620 and the vent valve 650 isshown in the waveforms of FIG. 49, which are repeated at an exemplaryrate of between approximately 1 Hz and approximately 250 Hz, further,between approximately 2 Hz and approximately 20 Hz, still further,between approximately 4 Hz and approximately 12 Hz, in particular,between approximately 6 Hz and approximately 8 Hz. At time 1, the vacuumvalve 620 is in the open/on position and the vent valve 650 is in theclosed/off position. At approximately time 2, the vacuum valve 620starts transitioning to the closed/off position. At approximately time3, the vacuum valve 620 is closed/off. At time 4, the vent valve 650starts to open and at approximately time 5, the vent valve 650 is fullyopen. The vent valve 650 remains open while the vacuum valve 620 isclosed until time 6, at which the vent valve 650 starts to close. Thevent valve 650 is closed at approximately time 7. The vacuum valve 620starts to open at time 8 and is partially open at approximately time 9.The vacuum valve 620 is full open when near the bottom extent of thecurve in the graph. This process is repeated periodically, which in thisexample is at 10 Hz.

In what is referred to herein as static aspiration, the distal end 664of the catheter 660 is pushed against a thrombus 4 while suction isapplied to the catheter 660. The lower pressure in the catheter 660creates a force on the clot 4 equal to a pressure differential acrossthe clot 4 multiplied by the area of the inner diameter of the catheter660. It is this force that “sticks” the clot 4 to the distal end 664 ofthe catheter 660 in an attempt to retrieve the clot 4 entirely.

In the ROAR cycle, suction is applied to the clot by rapidly opening avalve, causing a rapid rise in vacuum pressure. The source of suction isthen turned off and a vent fluid source is rapidly opened. This relievesthe vacuum present in the catheter 660, which again rapidly changes thepressure applied to the clot. The vent valve 650 is then rapidly closedand the vacuum valve 620 is rapidly opened. This cycle is repeatedmultiple times per second. For example, the period for repetition isbetween approximately 2 Hz and approximately 16 Hz, in particular,between approximately 8 Hz and approximately 12 Hz. The rapid drop ofpressure across the clot 4 when the vacuum valve 620 is opened causesthe clot 4 to accelerate into the lumen 662 of the catheter 660. Therelease of vacuum pressure when the vent valve 650 is opened causes theclot 4 to rebound back from the catheter 660. When the vacuum is appliedagain, the clot 4 once again accelerates towards the catheter 660. Theseaccelerations and rebounds cause the distributed mass of the clot 4 tooscillate. The large internal accelerations of the distributed mass fromthe oscillation creates internal forces in the clot 4 that are highenough to exceed the tensile strength of the clot 4 and cause it tofail. The torn pieces of clot 4 are then aspirated all the way throughthe catheter 660 and into the vacuum collection canister 612. Tomaximize forces in the clot, the pressure differential across the clotand the rate at which this differential pressure is applied ismaximized. The higher the rate at which this force is applied to theclot, the higher the internal acceleration of the distributed mass ofthe clot, and thus the higher the internal forces within the clot, andthus the higher the likelihood of the clot to tear. The times for thepressure change in both the up and down directions are about 20 mseither way. At 8 Hz, for example, each cycle is 125 ms and at 12 Hz eachcycle is 83 ms. The greater the frequency of the cycle, the greater thenumber of these impacts that the catheter can have to interact with theclot. Using higher frequencies is, therefore, better, but only up to apoint where there is not enough time to cause an effective enoughpressure delta within each cycle.

During operation of the catheter 660 with the ROAR effect, measurementof the pressure pulse can be undertaken with the proximal and distalpressure measurement devices 690, 692. The graph of FIG. 50 illustratespressure sensed by these devices 690, 692 during the exemplary 10 Hzpulse present in FIG. 49 (FIG. 51 illustrates the graphs of FIGS. 49 and50 superimposed on one another). The pressure sensed by the proximalpressure measurement device 690 starts at the lower pressure value(approximately at −13 psi) and the pressure sensed by the distalpressure measurement device 692 starts at a higher pressure value(approximately at −11 psi). This represents a partially corked systemwhere an incomplete seal of the thrombus simulant to the catheter allowssome flow by creating a slightly lower pressure at the distalmeasurement. At time 4, vacuum is off and the vent valve 650 starts toopen. Accordingly, vacuum in the lumen 662 starts to be relieved. Thismeans that pressure at the proximal pressure measurement device 690starts to increase, which is evidenced by the upwards curve starting atapproximately 4′. A short while later, as the change in pressurepropagates distally down the catheter 660, pressure at the distalpressure measurement device 692 starts to increase, which is evidencedby the upwards curve starting at approximately 4″. At time 6, the ventvalve 650 starts to close and, therefore, no more vent liquid 642 isentering the manifold 630 to add to or augment the fluid column in thelumen 662. Pressure at the proximal pressure measurement device 690,nonetheless, continues to rise as the vacuum (negative pressure) isentirely removed or is compensated by the pressure of the vent liquid642. Pressure at the proximal pressure measurement device 690 peaks and,as shown in FIG. 50, the pressure at the peak is at a positive pressureof approximately 2 psi—this occurs even though the aspirationthrombectomy system 600 does not actively apply any positive pressure tothe fluid or the lumen 662. Rather, this level of pressure being >0.0psi is due to the momentum of the fluid traveling within the lumen 662.Thus, a positive pressure within the lumen 662 is acceptable but itneeds to be suppressed before arriving at distal end. At time 8, thevent valve 650 has already closed and the vacuum valve 620 starts toopen at approximately the time of peak pressure at the proximal pressuremeasurement device 690. Opening of the vacuum valve 620 drops pressurewithin the lumen 662 and stops pressure at the proximal pressuremeasurement device 690 from going any higher (if not stopped at thislevel, then it is possible that pressure at the distal pressuremeasurement device 692 would be >0.0 psi, which means distal forwardflow will occur out from the distal end). Quelling of the pressure pulseis proven by review of the pressure track of the distal pressuremeasurement device 692. As can be seen in the graph of FIG. 50, thepressure increase at the distal pressure measurement device 692 followsthe pressure increase at the proximal pressure measurement device 690.At time 8, pressure recorded at the distal pressure measurement device692 is still negative (approximately at −5 psi), but is rising. Withcontinued operation of vacuum to and past time 9 (when the vacuum valve620 is fully open), the peak pressure measured at the distal end 664 bythe distal pressure measurement device 692 is less than 0.0 psi(horizontal dashed line), which means that the pressure pulse is quelledand that liquid from the distal portion does not exit the distal end664, in other words, substantially no forward flow. The ROAR effectallows the clot simulant to remain sealed to the catheter and the system600 is able to achieve the full vacuum of −13 psi at both measurements.Because the distal pressure is relieved almost to zero but then shortlyarrives at the full −13 psi vacuum, the pressure delta illustrated isapproximately 13 psi.

As described herein, it is possible to force flow from the distal end664 of the catheter 660 while cycling between vacuum and vent. The rapidswitching between vacuum and vent creates forward flow pressure pulsesin the fluid column that, if not managed, will force the fluid columnout of the distal end 664 of the catheter 660. The waves move throughthe fluid column at a very high speed through the medium. The speed isprimarily a function of the density of the fluid, the compliance of thesystem (the bulk modulus), and the length of the fluid column. Toprevent these waves from forcing the fluid column out of the catheter,the system is considered as a whole and the parameters of the valveswitching cycle are set such that the forces that cause the fluid columnto flow are controlled. To ensure that the fluid column does not exitthe distal end 664 of the catheter 660, it is important that thecatheter 660, any extension tube that connects to the catheter 660, thecontroller 700, and the valving sequence be tuned as a system.

The goal of the tuning process is at least two-fold: prevent thepressure waves generated during ROAR operation from causing forward flowand optimize the ROAR effect. The length of the fluid column is criticalto the tuning of the system. The pressure wave moves rapidly within thefluid column. The time for the wave to reach the distal tip of thecatheter is a function of this speed and the length of the fluid column.The speed is a function of the density of the fluid in the column andthe bulk modulus of the catheter and extension. The bulk modulus refersto the compliance of the system: both the radial and the longitudinalflexibility of the catheter and the extension tube. The density of thefluid column is not as significant a variable as the bulk modulus unlessit changes greatly, such as is the case if the fluid column has gaseous(air) bubbles in it. It is thus, important, to have all air purged fromthe system prior to implementing ROAR operation. For a given catheterand extension tube configuration, the bulk modulus and the length of thesystem is fixed. Compliance can be added to the system to change thespeed and thus tune the timing of the pressure wave. A flexible lengthof tubing could be added in-line with the relatively stiff catheter andextension, for example. This flexible length of tubing expands as thepressure pulses occur during ROAR operation. This decreases the bulkmodulus of the system and reduces the speed, thus slowing down thepressure wave and increasing its transit time to the distal tip of thecatheter. Compliance can be added in other ways as well, such as byincluding a piston backed by a spring in a bore that communicates withthe catheter lumen such that the pressure wave displaces the piston,which increases compliance of the system. By manipulating the complianceand the valve timing, the system can be tuned for many differentcombinations of catheters and extension lines. Careful tuning results inachieving a resonant condition. If the suction and release pulses in thecatheter are tuned to match a natural frequency of the clot, enhancedROAR effect can be achieved.

Tuning can happen statically or dynamically. A statically tuned systemis tuned so that the catheter 660 (and any extension tube that connectsto the catheter 660) is mated to the controller 700 with a fixed valvingsequence (such as the exemplary configuration shown in FIGS. 29 and 30).The controller 700 senses the presence of the catheter 660 when it isattached and verifies that it is the correct one for the tuned sequenceof that controller 700. If the correct catheter is not sensed, the tunedsequence does not initiate. A dynamically tuned system is, incomparison, tuned during operation. Prior to operation, a valve sequenceis initiated that creates a series of pressure pulses in the catheter660. Sensors, such as strain gauges, on the catheter 660 and/or anextension tube detect these pulses and are used to adjust parameters ofthe controller 700 for operation to create the ROAR effect. The catheter660 contains and transmits critical data, such as its length, to thecontroller 700. Using this tuning, any catheter, within limits, could beused without causing the fluid column to flow from the distal end 664during ROAR operation. Alternatively, the catheter 660 and the extensioncan be tuned at the manufacturer and the specifics of the valve timingcan be transmitted to the controller 700 by the catheter 660.

In an exemplary embodiment, the valve sequence is as follows:

the vacuum valve 620 is closed;

a time later the vent valve 650 is opened;

a time later the vent valve 650 is closed;

a time later the vacuum valve 620 is opened; and

a time later the sequence is repeated.

When the vent valve 650 is opened, a bit of vent liquid 642 enters thesystem and creates a pressure pulse. If the vent valve 650 is notclosed, and the vacuum valve 620 is not opened before the pulse reachesthe distal end 664 of the catheter 660, the fluid column will exit thedistal end 664 of the catheter 660 as forward flow. To prevent the fluidcolumn from exiting the catheter 660, it is this time—the time that ittakes for the pressure pulse to traverse the catheter—for which thesystem must be tuned. Additionally, the pressure pulse from closing thevacuum valve 620 in a flow condition will cause a pressure increase thatmust be quelled by opening the vent valve 650 before it causes forwardflow.

Tuning is accomplished by selecting appropriate times for the vacuumcycle and the vent cycle. In this regard, the vacuum cycle includesVacon time 622, Vacon duration 624, Vacoff time 626, and Vacoff duration628 and the vent cycle includes Vnton time 652, Vnton duration 654,Vntoff time 656, and Vntoff duration 658. Accordingly, tuning isexplained with reference to FIG. 52. A cycle time is the duration of therepetition of the entire cycle. At 8 Hz, the cycle time is 125 ms and at12 Hz, the cycle time is 83.33 ms. The cycle time is determined byadding the Vacon duration 624, the Vnton duration 654 and the first andsecond times in the cycle that both the vacuum and vent valves 620, 650are off, referred to as the “double-off’ or “double-closed” times orstates. The cycle time is optimized by the dynamics or the resonance ofa particular catheter 660. The Vacon duration 624 must be long enoughfor the system to pump down to full vacuum and the longer the vacuum ison during a particular cycle, the better the aspiration of the thrombus4. In this embodiment, opening only the vacuum valve is referred to asthe “vacuum-only” state. The first double-off time, which is the timeafter the vacuum is turned off (vacuum valve 620 closed) up until thetime that venting begins (vent valve 650 opens), has an effect on theextent to which forward flow occurs. As this is a short time, suchforward flow is referred to as flow burping. Through experimentation, anexemplary embodiment of an 0.071″ inner diameter catheter 660experiences flow burping when the first double-off time is greater thanapproximately 30 ms; the longer the double-off time, the greater flowburping. During ROAR operation, the first double-off time is about 10ms; therefore, this is significantly less than the flow burpingthreshold, which means that substantially all forward flow is quelled.The Vnton duration 654 is determined by a maximum time that occursbefore a corked clot 4 is dropped from forward flow. A ratio between theVnton duration 654 and the second double-off time is a compromise forthe longest Vnton time 654 and a minimum of the first double-off time.In this embodiment, opening only the vent valve is referred to as the“vent-only” state. Finally, with respect to the second double-off time,the vent valve 650 is off (fully closed) before the vacuum valve 620 isopened and vacuum recommences.

The calculation is explained further with regard to the valve positiongraphs in FIG. 53. Starting from the left of the graph at Vacon time622, the vent valve 650 is closed and the vacuum valve 620 is open. TheVacon duration 624 is long enough for the system 600 to pump down tofull vacuum (between approximately 10 ms and approximately 50 ms, inparticular, approximately 30 ms). The longer the Vacon duration 624, thebetter the catheter 660 performs because of increased flow rate in theproximal direction. There is a compromise based on achieving a higherfrequency for more hits/sec on the clot 4. In an exemplary embodiment,the Vacon duration 624, calculated from the Vacon time 622 to the Vacofftime 626, is between approximately 40% and approximately 60% of thecycle time 629. As set forth above, the cycle time 629 is a minimumdetermined by summation of Vacon duration 624 plus the first and seconddouble-off times 625, 627 plus the Vnton duration 654. The Vntonduration 654 is short enough to fill the lumen with vent liquid withoutcausing forward flow (between approximately 10 ms and approximately 50ms, in particular, approximately 30 ms). The first double-off time 625is set based upon when open flow burping occurs. The maximum value forthe first double-off time 625 applies to either of the periods from theVacoff time 626 to the Vnton time 652 or the Vacoff time 626 to theVacon time 622′ whichever is shorter. Each of these values are optimizedby the dynamics/resonance/compliance/length of the particular catheter660 and extension set.

From this, some observations can be made. When the vent is opened, apressure pulse is generated. It is important to stop the pressure pulsebefore it reaches the distal end. If the pressure pulse is not stoppedbefore it reaches the distal end, the catheter 660 will experienceforward flow. The way to stop the pressure pulse is to either close thevent and/or turn the vacuum back on if the vacuum was off prior toventing. If the vacuum remains on, then there is a need to turn the ventoff. Or, if the vacuum does not remain on, the vent is turned off andthe vacuum is turned back on before the pressure pulse makes it to thedistal end 664. In other words, the vent needs to be closed before thepressure pulse makes it to the distal end 664 and the vacuum has to beturned on. So, the condition of merely opening the vacuum valve 620 whenthe vent valve 650 is opened may not be enough to quell the pressurepulse because of the low resistance between the vent and the vacuum; thevent will overwhelm the vacuum so the vacuum cannot have an effect overthe length of the catheter. The time that it takes for the pressurepulse to propagate to the tip of the catheter 660 and then cause forwardflow is used to define the time that the vent valve 650 is left open.The time that the vent is left open is selected to be shorter than thetime it takes for the pressure pulse to propagate to the distal end 664.

In an exemplary embodiment illustrated diagrammatically in FIG. 55, allportions of the aspiration thrombectomy system 600 except for the ROARcatheter 660 are incorporated into the body 601 of the vacuum source610. In particular, the vacuum source 610 comprises the body 601, acollection canister 612, and a vacuum motor 614. The vacuum motor 614 isfluidically connected to an outlet of the collection canister 612 andthe input of the collection canister 612 is fluidically connected to avacuum side of the manifold 630. Accordingly, vacuum generated by thevacuum motor 614 imparts vacuum within the collection canister 612 todraw fluid into the collection canister 612 from the manifold 630 butnot into the vacuum motor 614. The vacuum valve 620 present at themanifold 630 prevents input fluid received at the manifold 630 fromentering the collection canister 612 and closes off the manifold 630from vacuum generated by the vacuum motor 614. The vent fluid reservoir640 containing the vent liquid 642 is fluidically connected to a ventside of the manifold 630. The vent valve 650 present at the manifold 630closes off the manifold 630 from the vent liquid 642 and prevents liquidwithin the manifold 630 from entering the vent fluid reservoir 640 (aspressure in the manifold 630 is typically lower than pressure within thereservoir 640, liquid from the manifold 630 will not typically enter thereservoir 640). In summary, a catheter input port 631 of the manifold630 is fluidically connected to the collection canister 612 through thevacuum valve 620 and is fluidically connected to the vent liquid 642 inthe reservoir 640 through the vent valve 650. The catheter input port631 is fluidically connected to the downstream end of the proximalmanifold connector assembly 670. The upstream end of the proximalmanifold connector assembly 670 is fluidically connected to the proximalend of the catheter 660.

Direct connection of the catheter 660 to the aspiration thrombectomysystem 600 is explained with regard to FIGS. 54 and 55. The proximalmanifold connector assembly 670 connects the proximal end 666 of theROAR catheter 660 to the manifold 630. In an exemplary embodiment shownin FIG. 54, the proximal manifold connector assembly 670 comprises amale luer lock fitting 672 connected to the manifold 630 (shown indashed lines), either removably or integrally. The assembly 670 includesa ROAR identification (ID) sub-assembly 680. The exemplary embodiment ofthe ID sub-assembly 680 shown in FIG. 54 comprises an inductive sensingdevice or sensor 682 connected to the manifold 630. The inductive sensor682 detects the presence of an inductive sensed part 684 that is presentin or integral with the proximal manifold connector assembly 670. In anexemplary embodiment where the manifold 630 can be used with variousdifferent ROAR catheters 660, each of the types of ROAR catheters has aunique inductive sensed part 684 and the inductive sensor 682 of themanifold 630 is able to determine which type of ROAR catheter 660 isattached. Accordingly, with an appropriate communication of the ROARcatheter 660 type to the controller 700, the controller 700 is able tooperate the ROAR catheter 660 according to its own unique configurationto produce the ROAR effect for every one of the different ROAR catheters660 that are used. When the sensor 682 does not detect a sensed part 684and the aspiration thrombectomy system 600 is, nonetheless, operated,the controller 700 will automatically prevent ROAR operation ofaspiration thrombectomy system 600 and that connected catheter will onlybe operated as a standard vacuum catheter.

Indirect connection of the catheter 660 to the aspiration thrombectomysystem 600 is explained with regard to FIG. 56. The proximal manifoldconnector assembly 670 can simply be a fitting 672 as shown in FIG. 54or it can be or include a separate extension line 674 between thecatheter input port 631 and whatever catheter 660 (standard or ROAR)that is to be used along with the aspiration thrombectomy system 600. Inan exemplary embodiment of the extension line 674, not only does theextension line 674 comprise a lumen extension for aspiration through thecatheter 600, the extension line 674 also comprises system controls foroperating the aspiration thrombectomy system 600. These controlsinclude, for example, turning on and off the vacuum motor 614 andturning on the ROAR operation (e.g., one button for each of these or anon/off switch for vacuum and a push-to-start button for ROAR). As shownin the diagram of FIG. 56, the extension line 674 has a distal end thatis able to connect to both standard catheters and ROAR catheters 600—asboth can be used with the aspiration thrombectomy system 600. When thestandard catheter is connected to the extension line 674, the aspirationthrombectomy system 660 only acts as a standard vacuum pump and ROAR isdisabled. When a ROAR catheter 660 is connected to the extension line674, identification sub-assemblies in the ROAR catheter 660 and theextension line 674 inform the system 600 which ROAR catheter 660 andwhich extension line 674 are connected.

In the exemplary embodiments with digital control of the vacuum and ventvalves 620, 650, a processor and memory in the controller 700 stores theidentification data and, upon identification of a particular ROARcatheter (e.g., different lengths, different outer diameters, differentmaterials), the controller 700 loads the valve sequence and operates thevacuum and vent valves 620, 650 according to the characteristics of theparticular catheter connected to the vacuum source 610. In one exemplaryembodiment, the identification data can be preprogrammed at themanufacturer for all ROAR catheters 660 that currently exist. Thus, withdirect connection of the ROAR catheter 660 to the system 600, thecontroller 700 can operate without receiving any information other thanthe identity of the catheter 660. If a ROAR extension line 674 is usedbetween the ROAR catheter 660 and the controller 700 (in other words, anextension line that is ROAR compatible and is able to inform the system600 of its augmentary characteristics to those of the ROAR catheter 660to which it is connected), the controller 700 can operate withoutreceiving any information other than the identity of the catheter 660and the identity of the intermediate extension line 674 becauseconnection with the ROAR extension line 674 allows the system 600 todetect which particular one of the different ROAR catheters 660 has beenconnected to the distal end of the ROAR extension line 674 and then tooperate ROAR in a predefined manner appropriate for that particular ROARcatheter 660 with the ROAR extension line 674. In the case of RFID ornear field communication (NFC), the chip embedded in the ROAR catheter660 is programmed with the specific valve timings required by thatcatheter 660. The controller 700 reads these values and functionsproperly for that catheter 660. This ensures future compatibility withnew generation catheters that require different tuning, which tuningwould not be known at the time the controller 700 is programmed at themanufacturer. If the catheter to be used is not a ROAR catheter 660,then ROAR should not be used with that catheter because of the highprobability of forward flow at the distal end. Accordingly, the system600 automatically prevents use of the ROAR effect when a non-ROARcatheter is connected to the distal end of the ROAR extension line 674or is connected directly to the system 600 or is connected to the distalend of a non-ROAR extension line 674.

The identification sub-assemblies include various measures present atleast at the proximal end of the ROAR catheter 660 (e.g., the inductivesensing system 682, 684 or a 1-wire detection system, such as a DALLASSemiconductor encryption chip, RFID, Bluetooth low energy (BLE),metallic touch pads, a simple passive design based upon resistors (inseries for catheter and extension, to name a few). In thesub-assemblies, there can be two or more electrical contacts. Forexample, there can be three contacts including power, ground, and asignal using a Hall sensor. In a two-contact configuration, there can bea 2-wire configuration using resistors and mechanical switches.Resistance can be measured between two contacts and, depending on theresistance, a state of the switch can be detected. Power and signal canbe combined on one line (plus an additional ground line) to create a“one-wire” connection, for example, using a DALLAS chip mentioned above.An identification sub-assembly also can be present at the distalconnection (e.g., a Luer fitting) of the extension line 674 (to contactwith the identification sub-assembly at the proximal end of the ROARcatheter 660) and extend back through the extension line 674 to acommunication connection with the vacuum source 610, e.g., the proximalmanifold connector assembly 670. Therefore, the aspiration thrombectomysystem 600 has an ability to sense/detect when a ROAR catheter 660 isconnected as differentiated from a standard catheter (i.e., not ROAR).Connection of the ROAR catheter 660 enables use of the ROAR function;connection of a non-ROAR catheter (or, e.g., to a side port of arotating hemostasis valve (RHV)) disables use of the ROAR function andonly normal aspiration is available. Where the identificationsub-assembly includes electrical contacts in the ROAR catheter 660, theconductive connection to the vacuum motor 614 can utilize one or morecoils of the ROAR catheter 660 as one of these conductors.Alternatively, two or more conductors can be wrapped within the ROARcatheter 660. Alternatively, or additionally, conductors can be bondedon the outside of the ROAR catheter 660.

In addition to the exemplary embodiments where the system 600 alreadystores the operating parameters for performing aspiration andautomatically uses those parameters when the ROAR catheter 660 and/orthe extension line 674 is connected or where the ROAR catheter 660 orthe extension line 674 provides the operating parameters for performingaspiration, the user can be provided with selectable programs in thecontroller. These selectable programs can be, in one exemplaryembodiment, programmed where the controller 700 is manufactured. Theuser has an instruction manual associating the particular ROAR catheter660 and/or the extension line 674 being used with a code that loads inthe operating parameters, such as pressures, delays, timing. Instead ofan instruction manual, these operating parameters can be manuallyentered by the user instead of through the selectable program(s), forexample, by reading the information the instructions for use (IFU) orthe packaging of the system 600, or ROAR catheter 660, or extension line674. In addition, if the user has a desired method of operation (forexample, to increase a particular timing), the user can enter theparameter(s) directly through a user interface on the system 600. Inother exemplary embodiments, a code supplier (e.g., a QR code, abarcode, or an RFID chip) could be on the packaging of one or more ofthe components and the user presents that code supplier to thecontroller for reading. In this regard, the system 600 comprises abar-code reader and/or a QR code reader and/or an RFID communicationdevice. With a display on the system 600, in another exemplaryembodiment, the screen presents parameters to the user and thoseparameters could be fixed or alterable by the user. In other words, theuser could accept or alter the parameters shown. In a particularlyinexpensive embodiment, the parameters can be “stored” on a punch cardthat is supplied with the ROAR catheter 660 or the extension line 674and the system 600 has a punch card reader. In this embodiment, the userinserts the inexpensive card (e.g., provided with a covering thatprotects it from liquids present in the operating room) into the cardreader and the controller 700 utilizes the parameters on the card orutilizes a code on the card, which code is associated with a set ofstored parameters.

All of these embodiments could present the operator with a choice ofalternative programs or parameters, or the system 600 could list theparameters that are about to be utilized separately on a display screenand then allow the operator to select those parameters or alter theprovided parameters. Similarly, operators are able to storeparameters/programs into empty memories within the controller 700. Thestored information provided by the catheter, the extension line, thecard, the code, etc., could be either ROAR parameters or, alternatively,the information can be characteristics of the catheter and the extensionline so that the controller 700 could make compensations to provide apredefined ROAR waveform at catheter tip. In other words, rather thanoffer up stored ROAR programs, the catheter and the extension line couldsimply give information to the controller 700 so that the timing andpressures could be modified for each catheter/extension line combinationto achieve the predefined ROAR pressure/time profile. By storing eithercompensation parameters or actual time/pressure parameters, thecontroller 700 is able to allow future catheters and extensions not yetavailable. Further, chips, resistors, RFIDs, or BLE could be used toprevent use of the system 600 with catheters not provided by themanufacturer of the system 600, and/or to present a warning or alarmcondition to the operator so that they know that the catheter and/orextension is not supported by the system 600.

One exemplary embodiment of the proximal manifold connector assembly 670comprises the extension line 674 having a system control board 676 withremote controls 678 illustrated in FIG. 56. An exemplary embodiment ofthe remote control 678 is a mechanical slide switch that turns vacuum onor off based upon a longitudinal position. This can be a two positionswitch with a button for ROAR operation. Alternatively, a three-positionswitch can be provided. In a forward position, the vacuum is off, in amiddle or intermediate position the vacuum is on, and in a rear positionROAR operation takes place. When the remote switch is connected, anycontrol buttons on pump are disengaged but the pump can have an“emergency off’ switch on the pump that allows the user to turn off thepump if desired regardless of the operation of the remote controls. LEDscan be provided on the remote controls 678 and/or on the body 601. TheseLEDs can, for example, be: Red=off, Green=Vacuum on, BlinkingGreen=ROAR, Blinking Red=Error, Blue=vent/purge. In an exemplaryembodiment, a mechanical redundant pinch valve is present againstcatheter that, when actuated, pinches closed the lumen of the catheter.In the exemplary embodiment, the distal end of the proximal manifoldconnector assembly 670 that connected to the ROAR catheter 660 comprisesa luer lock part that connects to another luer lock part on the ROARcatheter 660. In various exemplary embodiments, the switch is passive(e.g., a simple mechanical switch) or it is an active switch (e.g.,capacitive, pressure, magnetic). In such a case, the switch is poweredby wires through the extension line 674. In an alternative embodiment,the switch is a separate module that attaches to the extension line 674and is, for example, battery-powered.

A first benefit of the aspiration thrombectomy system 600 is that, withsuch a configuration, the same vacuum source 610 can be used with allcatheters that previously could be connected to any surgical aspirationdevices/vacuum pumps. A second advantage relates to security forenacting the ROAR effect. In such a configuration, users are persuadedto connect the proximal end of the ROAR catheter 660 to the distal endof the proprietary extension line 674. This is beneficial for variousreasons. First, ROAR will not work unless the two unique ROAR parts aredirectly connected and a positive ROAR ID is established. Second, if astandard rotating hemostasis valve is connected between the ROARcatheter 660 and the extension line 674 (for whatever reason that thesurgeon/nurse may have), then identification will be negative and ROARwill be disabled. There is a risk that fluid contained within lumens ofsuch rotating hemostasis valves will enter into the ROAR catheter'sfluid column and, thereby, introduce air bubbles, which need to bepurged entirely from the system for use. An RHV 609 increases theprobability of air remaining in the lumens or entering the fluid system.See FIG. 72. Thus, a particularly desirable configuration for the ROARcatheter 660 is a direct connection between the proximal end of the ROARcatheter 660 and a distal end of the proprietary extension line 674.There is also an issue of safety to ensure that the ROAR effect isutilized only with ROAR catheters 660. As described above, each ROARcatheter 660 has a particular set of characteristics related tocompliance and, therefore, operation of the vacuum and vent valves 620,650 is set for that characteristic set. The system 600 is set to reactwith a particular ROAR configuration based upon the physicalcharacteristics of the ROAR catheter 600 connected, such as length andlumen size. Therefore, the system 660 is tuned/programmed to store agiven ROAR setting for each ROAR catheter 660.

However, it is possible that new ROAR catheters 660 and new ROARextension lines 674 are created after the system 600 or the controller700 are put into the field. Providing the identity of the ROAR catheter660 or the ROAR extension line 674 would, therefore, not be sufficientto permit operation of those components properly. Thus, in an additionalor alternative embodiment, each of the ROAR catheters 660 and the ROARextension lines 674 are provided with a memory device (e.g., a DS28E07EEPROM memory chip) that, when connected to the system 600, provides thecontroller 700 with the variables necessary for that ROAR catheter 660and/or that ROAR extension line 674 to operate with the ROAR effect.Example variables that are stored in the memory of each of the ROARcatheters 660 and the ROAR extension lines 674 include, but are notlimited to, the frequency of the waveform cycle, a time in the cycle atwhich the vacuum turns on (Vacon time 622), a duration of the vacuum(Vacon duration 624), a time in the cycle at which the vacuum turns off(Vacoff time 626), a duration that the vacuum is off (Vacoff duration628), a time in the cycle at which the vent turns on (Vnton time 652), aduration of the vent (Vnton duration 654), a time in the cycle at whichthe vent turns off (Vntoff time 656), and/or a duration that the vent isoff (Vntoff duration 658). By being able to provide such information tothe controller 700, the system 600 can utilize any future ROAR catheter660 and/or ROAR extension line 674 that might be created for use withthe system 600.

An exemplary embodiment of a self-contained aspiration thrombectomysystem 600 is shown in FIGS. 57 to 71. The system 600 has an exteriorbody 601 containing therein a vacuum motor 614, the controller 700, andcontrols for the vacuum and vent valves 620, 650 (exemplary embodimentsof the controls for the valves are shown in FIG. 29 and FIGS. 42 to 46).The vacuum motor 614 is fluidically connected to a collection canister612 (shown diagrammatically with dashed lines). The body 601 houses aset of system controls 676 (in an alternative embodiment, the controls676 can be located on/also located on the extension line 674). In thisexemplary embodiment, there are three buttons: off, purge, and ROAR/Vac.(The purge function will be described in further detail below.) On aside opposite the collection canister 612 is a vent fluid reservoir 640(shown diagrammatically with dashed lines) containing therein ventliquid 642. As mentioned above, the fluid path of the catheter 660 is tobe free from bubbles/air at all times during a surgical procedure.

The body 601 has cassette connection assembly 602 on a front facethereof. The cassette connection assembly 602 protrudes from the frontface and has an exterior shape substantially the same as a cassette 710that will be attached thereto. The vacuum and vent valves 620, 650protrude from the front face 608 of the cassette connection assembly 602and, in an exemplary embodiment, are centered within respectivedepressions of the cassette connection assembly 602. In this embodiment,the vacuum and vent valves 620, 650 are pistons that have at adistal-most end thereof a pinching structure. In this exemplaryembodiment, the pinching structure is substantially in the shape of astandard slot screwdriver. As the vacuum and vent pistons extend outfrom the depression a given distance (e.g., 8 mm), the slot pressesagainst tubing (in the cassette 710) to close off the lumen within therespective vacuum or vent hose. Closing off the hose acts as a shut-offof the respective valve and releasing away from the hose acts to openthe vacuum or vent, respectively. Thus, if the hoses for each of thevacuum and vent lines are placed directly in front of the pistons, thevalves 620, 650 will control vacuum and vent according to the ROARprocess described herein. (As described below, the cassette 710positions those hoses in this manner.) In between the valves 620, 650 isa boss 604 protruding from the front face 608 of the cassette connectionassembly 602. The boss 604 has an exterior surface with a given shape,e.g., a raceway, and orientation wings 605. At the end of the boss 604is a rotating lock 606 in the shape of half circle or half oval. Therotating lock 606 has a central pivot to allow it to rotate 90 degreesfrom the position shown in FIGS. 57 to 67. In the rotated orientation,therefore, the rotating lock 606 defines lower surfaces (opposite thefront face 608 of the cassette connection assembly 602) that areperpendicular to the protruding extent of the boss 604. These lowersurfaces are set at a distance to define a gap between the lower surfaceof the rotating lock 606 and the front face 608 of the cassetteconnection assembly 602. Also present on the front face 608 of thecassette connection assembly 602 is/are conductive connectors 618. Theconductive connectors 618 are used to detect when a cassette 710 ispresent and locked on the cassette connection assembly 602. Detection ofthe cassette 710 can be made by mechanical measures (such as a pogo pin)or a combination of mechanical and optical and electrical measures.

A cassette 710 is removably connected to the cassette connectionassembly 602 and an exemplary embodiment of this cassette 710 isillustrated in FIGS. 68 to 71. As shown in FIG. 68, the cassette 710 hasan interior orifice 712 with a shape corresponding to the given shape ofthe boss 604. The boss 604 and interior orifice are matched in shape sothat the cassette 710 can fit onto the boss 604 and slide down thereonuntil the rear face of the cassette 710 aligns with and/or touches thefront face 608 of the cassette connection assembly 602. The rear face ofthe cassette 710 is depicted in FIG. 69. In the view of FIG. 69, pockets714 corresponding in shape to the orientation wings 605 are present inthe interior surface of the cassette 710 at the interior orifice 712. Inthis regard, when the cassette 710 is slid down the boss 604, there isonly one orientation in which the cassette 710 can approach the frontface 608 in a lower-most position e.g., as in a key within a keyhole.This placement insures that the distal end effectors of the vacuum andvent valves 620, 650 are always aligned with vacuum valve area 720 andthe vent valve area 750 within the cassette 710.

When the “T” shape of the boss 604 and wings 605 are matched with theinterior T-shape of the orifice 712, three connections are madepossible. First, as set forth above, the distal end effectors of thevacuum and vent valves 620, 650 are aligned with vacuum and vent valveareas 720, 750 within the cassette 710. Second, conductive connectors718 on a rear face of the cassette 710 are aligned with and make contactwith respective conductive connectors 618 adjacent the boss 604. Theseconnectors 718, 618 can be, for example, respective pads and pogo pinsto insure positive electrical connection when the rotating lock 606 isused to lock the cassette 610 onto the body 611. With appropriateelectrical connections, these connectors 718, 618 can inform thecontroller 700 that the cassette 710 is installed and ready for use andwhich kind of cassette 710 is installed if it is associated with aparticular ROAR catheter 660 and needs identification. Finally, therotating lock 606 is located above the front face 608 of the cassetteconnection assembly 602 and the bottom surfaces of the rotating lock 606are above the outer front face 716 of the cassette 710. A protrusiondistance of the boss 604 is configured to place bottom surfaces of therotating lock 606 (those surfaces facing the front face 608) at adistance approximately equal to the thickness of the cassette 710 suchthat, with rotation of the lock 606, the bottom surfaces of the lock 606engage the outer front face 716 of the cassette 710, thereby pressingthe cassette 710 firmly in place against the front face 608 to touch theconnectors 718, 618 together and locking the cassette 710 to the body601. The quarter-turn rotating lock 606 secures the cassette 710 on thebody 601 and also provides a cam force that holds the cassette 710thereon, in particular, while the valves 620, 650 actuate against vacuumand vent tubing present within the cassette 710. In an exemplaryembodiment, a non-illustrated switch is integrated in the rotating lock606, the switch detecting the quarter-turn and, with the electricalconnectors 718, 618, verifying that the system 600 is armed and readyfor use.

In a particularly efficient configuration, the cassette 710 can beremovable, replaceable, and disposable as an entire set including thejunction box shown in FIGS. 68 to 71 and a tubing set. The cassette 710has as set of relatively short whips of tubing including a first tubingwhip 722 fluidically connected to the collection canister 612 of thevacuum source 610 and a second tubing whip 752 fluidically connected toan intake of the vent valve 650, and an extension whip that can be theextension line 674 or it can be a short tubing to be connected directlyto the catheter 660. Once connected, this efficient configuration allowsthe system of lumens to be automatically cleared of air/bubbles. Bylocating the vent liquid above all of the lumens (such as with the bag640 in FIG. 67), the catheter 660, and the collection canister, openingthe output of the vent fluid reservoir 640 will fill all interior lumensand clear the system of any air/bubbles before use. If desired, a camlock can be mechanically connected to the vacuum motor 614 (eithertemporarily or fixed) and the motor 614 can be operated to actively drawall air into the collection canister and thereby purge the system 600.As an alternative to the front-loaded configuration of the cassette 710,the cassette 710 can be connected or molded as a part of a bottom of thedisposable collection canister 612. In this configuration, twodisposable parts can be provided together in a sterile packaging anddisposed of in one piece. With a vent fluid reservoir that is either ahard container (FIGS. 57 to 61) or a bag (FIGS. 62 to 67), the ventliquid 642 can be part of the cassette 700 with all lumens pre-filledwith saline and part of a single disposable package. The vent fluidreservoir 640 and the collection canister 612 can either or both be partof a disposable cassette 700 system. All of the disposable parts used ina catheter procedure can be integrated together in one disposablepackage.

As explained previously, it is important for the system to be purged ofair to achieve the ROAR effect. Purging can be achieved in several ways.The two main methods used to purge the system are forced purged anddribble purge. The forced purge method involves submerging the tip ofthe extension line 674 into sterile fluid such as saline and whilesubmerged activating the “purge” function. The controller 700 will thenalternatively open one or both of the control valves for a predeterminedtime and sequence to pull the sterile fluid through the extension line674 and valves and displace all the air that may have been in thesystem. Once this purge process is complete, both valves will close andthe extension line 674 with a full fluid column can be connected to thecatheter which has also be de-aired and ROAR applied. In comparison, thedribble method relies on a small positive pressure (created by gravity,squeezing the fluid bag, pressurizing the vent fluid tank, or aperistaltic pump or any similar measures) to allow the vent fluid todribble through the lumens and, thus, flood them. In an exemplary caseof the dribble purge system, the vent fluid source 640 is higher thanthe exit of the extension line 674 and the vent liquid path does notcontain any air traps.

For the dribble method, the purge cycle is initiated by pressing thepurge button and, in an exemplary embodiment, is performed by thecontroller 700. With the vacuum valve 620 closed, the vacuum source 610is turned on and the vacuum vessel is pumped down to a desired vacuumlevel. The vent valve 650 is opened and vent liquid 642 is allowed toflood the vent line and the extension line 674. To ensure that all airis removed from the manifold 630, the vacuum valve 620 is openedmomentarily while the vent valve 650 is also open. This allows the ventliquid 642 to be drawn from the vent fluid source 640 and from theextension line 674, and through the vacuum manifold passageways thuspurging them of air. The vent valve 650 is left open for a period oftime after the vacuum valve 620 closes to ensure that the quantity offluid that the vacuum cycle removed from the extension line 674 isreplenished. This cycle of vent liquid flow and momentary vacuum can berepeated several times to ensure complete purging. The purge pump can bea peristaltic pump, a pressurized cuff around a flexible vent liquidcontainer (such as an IV bag), and/or a vent fluid canister pressurizedby using the exhaust from the vacuum source 610.

The presence of bubbles in the fluid system adversely affects thewater-hammer effect. Accordingly, the system 600 facilitates orautomatically purges air from the fluid lumens. In an exemplaryembodiment, bubble sensors (either optical, ultrasonic, orfluid-pressure-profile based) are incorporated into the system 600 tofacilitate this purging or to automatically engage a purging function(e.g., under operator control to prevent purging when the catheter 660is present in the bloodstream). There are various measures for bubbledetection. For example, an optical sensor could be placed in thecassette 710 to sense the presence of bubbles. With a sensor coupled tothe vacuum source 610, a slow rise in pressure can be sensed to preventusing the incorrect catheter or extension. The specific compliance of acatheter 660 or an extension line 674 is among the parameters used toprogram or compensate the system 600. A user-feedback indication informsthe user when the system has been sufficiently purged. In an exemplaryembodiment, the compliance of the catheter 660 and the extension line674 are controlled to be below some optimum range. Also, pressure-riseinformation is used to modify the ROAR settings, for example, to detectcorking and provide an optimum pressure profile for that condition.

The exemplary configurations of the aspiration thrombectomy system 600described and shown provide various significant benefits. Beforedescribing these additional benefits, reference is made to FIG. 72,which illustrates one exemplary embodiment of the aspirationthrombectomy system 600 with extension lines 674, and catheters 660. Theaspiration thrombectomy system 600 comprises the vacuum source 610 withthe collection canister 612, the vent liquid reservoir 640 with the ventliquid 642, the manifold 630, and the proximal manifold connectorassembly 670. Removably connected to the proximal manifold connectorassembly 670 is a ROAR extension line 674. Next to the ROAR extensionline 674 is an off-the-shelf extension line 674′ usable both with thesystem 600 by connecting through the proximal manifold connectorassembly 670 and with conventional surgical vacuum sources. The ROARextension line 674 comprises the system controls 676, which are alsoshown on a top surface of a frame of the system 600. Also shown is aROAR catheter 660 and an off-the-shelf aspiration catheter 660′. Withproximal Luer connectors, both catheters 660, 660′ can be used witheither extension line 674, 674′.

There are several topologies for the disposable, reusable, andlimited-reuse components of the aspiration thrombectomy system 600 asdescribed and shown herein. The vacuum source 610 can be a limited-reusecomponent that plugs into a reusable electronics/power-supply system,such as the frame in FIG. 72. The valve-element cassette 710 includespinch-tubes and, therefore, it is a single-use only component.Alternatively, the valving components can be reusable, for example,where the valve actuator is separate, either in a separate semi-reusablemodule, or part of the pump/control system. The different kinds ofvalves (e.g., rotary, trumpet) that have different ways to separate thedisposable/reusable portions of the system 600. The valve actuators canbe part of a reusable portion or part of a limited-reuse portion (e.g.,along with a pump module). Alternatively, the valve-actuators can be asecond limited-reuse module. The cassette 710 with the valve elementscan include a diaphragm or piston that is actuated by a mechanicalactuator in the reusable part of the system 600. With such modularity,the architecture of the system 600 becomes adaptable to use with anyvacuum source, even a household vacuum system (which could include avacuum pressure regulator to ensure uniformity of the system 600. Thepower source for the system 600 may be a rechargeable battery or areplaceable module attached to the system 600, in which case the latterdoes not require sterility. Alternatively, the power source is a primarybattery included as part of the disposable components, which couldinclude disposable pumping elements.

The various configurations permit multiple product topologiesspecifically targeted at different use cases. For example, one topologyis a minimum-recurring-cost system with only the tubing set beingdisposable. Alternatively, another topology is a system requiringminimum capital cost and incorporating modules whose costs are easilyamortized for each surgical case.

Various additional safety measures can be added to the system 600. Forexample, a liquid level detector can be provided at or with the ventfluid reservoir 640 to confirm that vent liquid 642 is within the tankor pouch, to indicate a warning to the user when the level of ventliquid is low, and to prevent operation of the system 600 if the ventliquid about to run out or is empty. In the configurations with thecassette 710, the system 600 will not start unless the cassette 710 isin place and is correctly installed. The system 600 can have a purgingfunction that is used to fill the various lumens of the catheter 660,the extension line 674, and any tubing connecting the vent fluidreservoir 640 and the collection canister 612 before use. It is notedthat the system 600 should not be operated if air is present anywhere inthe lumens. Thus, the controller 700 can operate the system to draw invent liquid 642 and fill the various lumens in a pre-use setup phase.This could include having the vacuum motor 614 operate in reverse toapply positive pressure for purging the various lumens. Alternatively,the controller 700 could actuate a peristaltic pump to purge vent fluidthrough the lumens. The controller 700 can be programmed, duringoperation of the system 600, to detect peaks of use during ROAR. Ifthese peaks are not sharp, then a conclusion that air is present in thesystem can be determined. Bubble detectors (i.e., ultrasonic) can beadded to the system such that they straddle the tubing in the cassetteand provide feedback to the controller to ensure that the tubing hasbeen properly purged. With such a conclusion, the controller 700 can beprogrammed to cease operation and start an auto-purge routine to flushthe various lumens with an external liquid source or from the vent fluidreservoir 640.

It is noted that various individual features of the inventive processesand systems may be described only in one exemplary embodiment herein.The particular choice for description herein with regard to a singleexemplary embodiment is not to be taken as a limitation that theparticular feature is only applicable to the embodiment in which it isdescribed. All features described herein are equally applicable to,additive, or interchangeable with any or all of the other exemplaryembodiments described herein and in any combination or grouping orarrangement. In particular, use of a single reference numeral herein toillustrate, define, or describe a particular feature does not mean thatthe feature cannot be associated or equated to another feature inanother drawing figure or description. Further, where two or morereference numerals are used in the figures or in the drawings, thisshould not be construed as being limited to only those embodiments orfeatures, they are equally applicable to similar features or not areference numeral is used or another reference numeral is omitted.

The foregoing description and accompanying drawings illustrate theprinciples, exemplary embodiments, and modes of operation of thesystems, apparatuses, and methods. However, the systems, apparatuses,and methods should not be construed as being limited to the particularembodiments discussed above. Additional variations of the embodimentsdiscussed above will be appreciated by those skilled in the art and theabove-described embodiments should be regarded as illustrative ratherthan restrictive. Accordingly, it should be appreciated that variationsto those embodiments can be made by those skilled in the art withoutdeparting from the scope of the systems, apparatuses, and methods asdefined by the following claims.

I/We claim:
 1. A method for removing thromboembolic material from aperson using aspiration, comprising: positioning a distal end of acatheter at least proximate to thromboembolic material in a blood vesselof the person; applying a vacuum through a lumen of the catheter suchthat a vacuum flow draws at least a portion of the thromboembolicmaterial into the catheter lumen; stopping the vacuum flow through thecatheter lumen such that a fluid column is positioned in the catheterlumen; causing the fluid column to shift in a distal direction along thecatheter lumen; limiting the shift of the fluid column to a displacementlimit of fluid at the distal end; reapplying the vacuum through thecatheter lumen thereby drawing the thromboembolic material into thecatheter lumen; and repeating the acts of stopping the vacuum flow,causing the fluid column to shift distally, limiting the shift of thefluid column and reapplying the vacuum through the catheter lumen. 2.The method of claim 1 wherein limiting the shift of the fluid columncomprises stopping the distal movement of the fluid column such that thedisplacement limit is approximately 0.001 ml to approximately 1.0 ml offluid that exits the distal end of the catheter before fluid is drawnback into the catheter lumen.
 3. The method of claim 1 wherein limitingthe shift of the fluid column comprises stopping the distal movement ofthe fluid column such that the displacement limit is approximately 0.1ml to approximately 0.5 ml of fluid that exits the distal end of thecatheter before fluid is drawn back into the catheter lumen.
 4. Themethod of claim 1 wherein limiting the shift of the fluid columncomprises stopping the distal movement of the fluid column such that thedisplacement limit is approximately 0.5 mm to approximately 30 mm offluid from the fluid column that exits the distal end of the catheterbefore fluid is drawn back into the catheter lumen.
 5. The method ofclaim 1 wherein limiting the shift of the fluid column comprisesstopping the distal movement of the fluid column such that thedisplacement limit is approximately 0.5 mm to approximately 15 mm offluid from the fluid column that exits the distal end of the catheterbefore fluid is drawn back into the catheter lumen.
 6. A method forremoving thromboembolic material from a person using aspiration,comprising: positioning a distal end of a catheter at least proximate tothromboembolic material in a blood vessel of the person; applying avacuum through a lumen of the catheter such that a vacuum flow draws atleast a portion of the thromboembolic material into the catheter lumen;stopping the vacuum flow through the catheter lumen such that a fluidcolumn is positioned in the catheter lumen; causing the fluid column toshift in a distal direction along the catheter lumen; limiting the shiftof the fluid column to a metered volumetric column shift at the distalend; reapplying the vacuum through the catheter lumen thereby drawingthe thromboembolic material into the catheter lumen; and repeating theacts of stopping the vacuum flow, causing the fluid column to shiftdistally, limiting the shift of the fluid column and reapplying thevacuum through the catheter lumen.
 7. The method of claim 6 whereinlimiting the shift of the fluid column comprises stopping the distalmovement of the fluid column such that the metered volumetric columnshift is approximately 0.001 ml to approximately 1.0 ml of fluid thatexits the distal end of the catheter before fluid is drawn back into thecatheter lumen.
 8. The method of claim 6 wherein limiting the shift ofthe fluid column comprises stopping the distal movement of the fluidcolumn such that the metered volumetric column shift is approximately0.1 ml to approximately 0.5 ml of fluid that exits the distal end of thecatheter before fluid is drawn back into the catheter lumen.
 9. Themethod of claim 6 wherein limiting the shift of the fluid columncomprises stopping the distal movement of the fluid column such that themetered volumetric column shift is approximately 0.5 mm to approximately30 mm of fluid from the fluid column that exits the distal end of thecatheter before fluid is drawn back into the catheter lumen.
 10. Themethod of claim 6 wherein limiting the shift of the fluid columncomprises stopping the distal movement of the fluid column such that themetered volumetric column shift is approximately 0.5 mm to approximately15 mm of fluid from the fluid column that exits the distal end of thecatheter before fluid is drawn back into the catheter lumen.
 11. Asystem for removing thromboembolic material from a blood vessel of aperson using aspiration, comprising: a catheter having a proximalportion, a distal end and a lumen extending therethrough, wherein thedistal end is configured to be placed at least proximate tothromboembolic material in a blood vessel of the person; a vacuum sourceconfigured to be fluidically coupled to the proximal portion of thecatheter; and a control system configured to (a) stop a vacuum flowthrough the catheter lumen such that a fluid column is positioned in thecatheter lumen when the distal end of the catheter is positioned atleast proximate the thromboembolic material, (b) cause the fluid columnto shift in a distal direction along the catheter lumen, (c) limit theshift of the fluid column to a metered volumetric column shift at thedistal end of the catheter, (d) reapply the vacuum flow through thecatheter lumen, and (e) repeat the acts of stopping the vacuum flow,causing the fluid column to shift distally, limiting the shift of thefluid column and reapplying the vacuum through the catheter lumen. 12.The system of claim 11 wherein the control system is configured to limitthe shift of the fluid column such that the metered volumetric columnshift is approximately 0.001 ml to approximately 1.0 ml of fluid thatexits the distal end of the catheter before fluid is drawn back into thecatheter lumen.
 13. The system of claim 11 wherein the control system isconfigured to limit the shift of the fluid such that the meteredvolumetric column shift is approximately 0.1 ml to approximately 0.5 mlof fluid that exits the distal end of the catheter before fluid is drawnback into the catheter lumen.
 14. The system of claim 11 wherein thecontrol system is configured to limit the shift of the fluid column suchthat the metered volumetric column shift is approximately 0.5 mm toapproximately 30 mm of fluid from the fluid column that exits the distalend of the catheter before fluid is drawn back into the catheter lumen.15. The system of claim 11 wherein the control system is configured tolimit the shift of the fluid column such that the metered volumetriccolumn shift is approximately 0.5 mm to approximately 15 mm of fluidfrom the fluid column that exits the distal end of the catheter beforefluid is drawn back into the catheter lumen.